feat(git): add grbia alias for interactive rebase with autosquash

`grbia` runs `git rebase --interactive --autosquash`, following the
existing `grbmia` naming. It has been proposed several times over the
years; this lands it and credits everyone who tried.

Fixes #13865

Co-authored-by: Tushar Mathur <194482+tusharmath@users.noreply.github.com>
Co-authored-by: Thomas Raimond <10564970+ThamosIO@users.noreply.github.com>
Co-authored-by: Clément <59260989+clegoffic@users.noreply.github.com>
Co-authored-by: Gaurav Yadav <160158213+MeGaurav4@users.noreply.github.com>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

plugins/git/README.md

@@ -156,6 +156,7 @@ plugins=(... git)
 | `grba`                 | `git rebase --abort`                                                                                                            |
 | `grbc`                 | `git rebase --continue`                                                                                                         |
 | `grbi`                 | `git rebase --interactive`                                                                                                      |
+| `grbia`                | `git rebase --interactive --autosquash`                                                                                         |
 | `grbmi`                | `git rebase $(git_main_branch) --interactive`                                                                                   |
 | `grbmia`               | `git rebase $(git_main_branch) --interactive --autosquash`                                                                      |
 | `grbo`                 | `git rebase --onto`                                                                                                             |

plugins/git/git.plugin.zsh

@@ -357,6 +357,7 @@ alias grb='git rebase'
 alias grba='git rebase --abort'
 alias grbc='git rebase --continue'
 alias grbi='git rebase --interactive'
+alias grbia='git rebase --interactive --autosquash'
 alias grbo='git rebase --onto'
 alias grbs='git rebase --skip'
 alias grbd='git rebase $(git_develop_branch)'