feat: delete-branch multiple unique branch names completions (#1221)

Author: johnpyp

etc/bash_completion.sh

@@ -1,6 +1,13 @@
 # shellcheck shell=bash
 # bash completion support for git-extras.
 
+__gitex_heads_unique() {
+  local branch specified=("${COMP_WORDS[@]:2}")
+  for branch in $(__git_heads); do
+    [[ " ${specified[*]} " == *" $branch "* ]] || printf '%s\n' "$branch"
+  done
+}
+
 _git_authors(){
   __gitcomp "-l --list --no-email"
 }
@@ -84,7 +91,7 @@ __git_cp(){
 }
 
 _git_delete_branch(){
-  __gitcomp "$(__git_heads)"
+  __gitcomp "$(__gitex_heads_unique)"
 }
 
 _git_delete_squashed_branches(){

etc/git-extras-completion.zsh

@@ -72,6 +72,15 @@ __gitex_branch_names() {
     _wanted branch-names expl branch-name compadd $* - $branch_names
 }
 
+__gitex_branch_names_unique() {
+    local expl
+    declare -a branch_names already_specified
+    branch_names=(${${(f)"$(_call_program branchrefs git for-each-ref --format='"%(refname)"' refs/heads 2>/dev/null)"}#refs/heads/})
+    __gitex_command_successful || return
+    already_specified=(${words[2,-1]})
+    _wanted branch-names expl branch-name compadd -F already_specified $* - $branch_names
+}
+
 __gitex_specific_branch_names() {
     local expl
     declare -a branch_names
@@ -196,8 +205,7 @@ _git-create-branch() {
 }
 
 _git-delete-branch() {
-    _arguments \
-        ':branch-name:__gitex_branch_names'
+    __gitex_branch_names_unique
 }
 
 _git-delete-squashed-branches() {