fix(main.py): makes default prompt correctly

[hzc989]

Description

default prompt option not working when exceeds max limit, which is 45 chars.

in this circumstance, only the databasename is show, which is a bit inconvenient and unexpected for information display.

Optimization PR

I made a PR to optimize it.

as image shown below, add a default prompt with \n for line splitting, when it exceeds the max length.

Checklist

• [x] I've added this contribution to the changelog.md.
• [x] I've added my name to the AUTHORS file (or it's already there).

[hzc989]

this fixes the issue https://github.com/dbcli/mycli/issues/1144

[amjith]

Thank you!

[your-diary]

@hzc989 @amjith Can you consider reverting this PR? I think this PR is not tested well; it breaks an existing important feature. See #1155.