Add command to rebase onto base branch

[stefanhaller]

• PR Description

In the rebase menu, add a command "Rebase onto base branch". This makes it more convenient to rebase onto master (or main), because

• you don't need to bring your local version of the base branch up to date first
• you don't have to remember which of your main branches (e.g. "main", "devel", or "1.0-hotfixes") your current branch is based on.

This is sitting on top of #3614.

Closes #3546.

• Please check if the PR fulfills these requirements

• [x] Cheatsheets are up-to-date (run go generate ./...)

• [x] Code has been formatted (see here)

• [x] Tests have been added/updated (see here for the integration test guide)

• [x] Text is internationalised (see here)

• [x] Docs have been updated if necessary

• [x] You've read through your own file changes for silly mistakes etc

[codacy-production[bot]]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
Report missing for 36a46965731bfc420b9d673071b4d6adda07d87e[^1]	:white_check_mark: 96.40%

Coverage variation details

| | Coverable lines | Covered lines | Coverage | | ------------- | ------------- | ------------- | ------------- | | Common ancestor commit (36a46965731bfc420b9d673071b4d6adda07d87e) | Report Missing | Report Missing | Report Missing | | | Head commit (a8921a13cb0acddf8fdac02c62a84cf478b9e2eb) | 51737 | 43662 | 84.39% | **Coverage variation** is the difference between the coverage for the head and common ancestor commits of the pull request branch: ` - `

Diff coverage details

| | Coverable lines | Covered lines | Diff coverage | | ------------- | ------------- | ------------- | ------------- | | Pull request (#3615) | 111 | 107 | **96.40%** | **Diff coverage** is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: `/ * 100%`

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_{Codacy will stop sending the deprecated coverage status from June 5th, 2024. Learn more} [^1]: Codacy didn't receive coverage data for the commit, or there was an error processing the received data. Check your integration for errors and validate that your coverage setup is correct.

[stefanhaller]

Thanks for the quick review. I hope I made it clear enough that this can only be merged after #3613 and #3614, because it is using code that was introduced there. If those take longer to review, I could restructure the commits so that I can merge this one independently, but it's extra work that I would like to avoid if possible.

Or was the LGTM meant for all three of them?

[jesseduffield]

The LGTM was only intended for this one :) I intend to get to those other two tonight

[stefanhaller]

Great, thanks. No rush from my side, I'm not in a hurry to get these merged (it just sounded a bit like you did 😄)