git: fix `gbda` trying to delete worktree branches (#8102)

Git learned to add a `+` in front of branches that are
checked out in other worktrees.

See: 745f681289/Documentation/RelNotes/2.23.0.txt (L252-L256)

plugins/git/README.md

@@ -22,7 +22,7 @@ plugins=(... git)
 | gb                   | git branch                                                                                                                    |
 | gba                  | git branch -a                                                                                                                 |
 | gbd                  | git branch -d                                                                                                                 |
-| gbda                 | git branch --no-color --merged \| command grep -vE "^(\*\|\s*(master\|develop\|dev)\s*$)" \| command xargs -n 1 git branch -d |
+| gbda                 | git branch --no-color --merged \| command grep -vE "^(\+|\*\|\s*(master\|develop\|dev)\s*$)" \| command xargs -n 1 git branch -d |
 | gbD                  | git branch -D                                                                                                                 |
 | gbl                  | git blame -b -w                                                                                                               |
 | gbnm                 | git branch --no-merged                                                                                                        |

plugins/git/git.plugin.zsh

@@ -42,7 +42,7 @@ alias gap='git apply'
 alias gb='git branch'
 alias gba='git branch -a'
 alias gbd='git branch -d'
-alias gbda='git branch --no-color --merged | command grep -vE "^(\*|\s*(master|develop|dev)\s*$)" | command xargs -n 1 git branch -d'
+alias gbda='git branch --no-color --merged | command grep -vE "^(\+|\*|\s*(master|develop|dev)\s*$)" | command xargs -n 1 git branch -d'
 alias gbD='git branch -D'
 alias gbl='git blame -b -w'
 alias gbnm='git branch --no-merged'