Use default `max_lines` when calling `up` & `down`

[HeyNonster]

Description

Both up and down only show 1 source line when called, I think it would be more useful if they provided more context. This removes the max_lines: 1 kwarg when they call show_src. max_lines in show_src will default to CONFIG[:show_src_lines]^1.

Big thanks to @st0012 for showing me and @bquorning where this behavior is defined.

[st0012]

I want to second this proposal as I also often need to chain whereami after moving to a different frame, which IMO is not the best user experience in most cases.

[HeyNonster]

Also probably useful to note that byebug displays more lines by default making it quite a difference switching from byebug to debug:

https://github.com/ruby/debug/assets/47484308/5f2174b9-1264-4753-be71-14203977c69f

[launchable-app[bot]]

Launchable Report

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_{:bell: no issues :heavy_multiplication_x:1 test failed :heavy_check_mark:63 tests passed}

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_{:bell: no issues :heavy_multiplication_x:1 test failed :heavy_check_mark:63 tests passed}

Passed test sessions

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passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907793) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907793) [details on CI](https://github.com/ruby/debug/actions/runs/9106425073) :white_check_mark: Test session [#2907794](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907794) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907794) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907794) [details on CI](https://github.com/ruby/debug/actions/runs/9106425073) :white_check_mark: Test session [#2907796](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907796) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907796) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907796) [details on CI](https://github.com/ruby/debug/actions/runs/9106425073) :white_check_mark: Test session [#2907798](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907798) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907798) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907798) [details on CI](https://github.com/ruby/debug/actions/runs/9106425073) :white_check_mark: Test session [#2907799](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907799) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907799) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907799) [details on CI](https://github.com/ruby/debug/actions/runs/9106425063) :white_check_mark: Test session [#2907800](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907800) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907800) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907800) [details on CI](https://github.com/ruby/debug/actions/runs/9106425063) :white_check_mark: Test session [#2907801](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907801) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907801) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907801) [details on CI](https://github.com/ruby/debug/actions/runs/9106425063) :white_check_mark: Test session [#2907803](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907803) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907803) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907803) [details on CI](https://github.com/ruby/debug/actions/runs/9106425063) :white_check_mark: Test session [#2907815](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907815) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907815) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907815) [details on CI](https://github.com/ruby/debug/actions/runs/9106425063) :white_check_mark: Test session [#2907818](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907818) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907818) 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:white_check_mark: Test session [#2907824](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907824) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907824) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907824) [details on CI](https://github.com/ruby/debug/actions/runs/9106425069) :white_check_mark: Test session [#2907825](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907825) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907825) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907825) [details on CI](https://github.com/ruby/debug/actions/runs/9106425069) :white_check_mark: Test session [#2907826](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907826) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907826) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907826) [details on CI](https://github.com/ruby/debug/actions/runs/9106425066) :white_check_mark: Test session [#2907829](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907829) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907829) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907829) [details on CI](https://github.com/ruby/debug/actions/runs/9106425069) :white_check_mark: Test session [#2907831](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907831) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907831) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907831) [details on CI](https://github.com/ruby/debug/actions/runs/9106425069) :white_check_mark: Test session [#2907834](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907834) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907834) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907834) [details on CI](https://github.com/ruby/debug/actions/runs/9106425069) :white_check_mark: Test session [#2907857](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907857) passed [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907857) [](https://app.launchableinc.com/organizations/ruby/workspaces/debug/data/test-sessions/2907857) [details on CI](https://github.com/ruby/debug/actions/runs/9106425069)

Build: refs_pull_1094_merge_b1963e7b72554c9672900ba046c3088598955488

[HeyNonster]

Seems the protocol tests are flaky: https://github.com/ruby/debug/pull/1060