feat(git): add merge squash alias (`gms`) (#10937)

plugins/git/README.md

@@ -116,6 +116,7 @@ plugins=(... git)
 | gloga                | git log --oneline --decorate --graph --all                                                                                                                                               |
 | glp                  | git log --pretty=\<format\>                                                                                                                                                              |
 | gm                   | git merge                                                                                                                                                                                |
+| gms                  | git merge --squash |
 | gmom                 | git merge origin/$(git_main_branch)                                                                                                                                                      |
 | gmtl                 | git mergetool --no-prompt                                                                                                                                                                |
 | gmtlvim              | git mergetool --no-prompt --tool=vimdiff                                                                                                                                                 |

plugins/git/git.plugin.zsh

@@ -237,6 +237,7 @@ alias gmtl='git mergetool --no-prompt'
 alias gmtlvim='git mergetool --no-prompt --tool=vimdiff'
 alias gmum='git merge upstream/$(git_main_branch)'
 alias gma='git merge --abort'
+alias gms="git merge --squash"
 
 alias gp='git push'
 alias gpd='git push --dry-run'