fix(_command_commnad): support bash-5.2 quoting in "complete -p"

Author: akinomyoga

bash_completion

@@ -2231,7 +2231,9 @@ _comp_command_offset()
         compopt -o filenames
         COMPREPLY=($(compgen -d -c -- "$cur"))
     else
-        local cmd=${COMP_WORDS[0]} compcmd=${COMP_WORDS[0]}
+        local ret
+        _comp_dequote "${COMP_WORDS[0]}" || ret=${COMP_WORDS[0]}
+        local cmd=$ret compcmd=$ret
         local cspec=$(complete -p "$cmd" 2>/dev/null)
 
         # If we have no completion for $cmd yet, see if we have for basename
@@ -2294,7 +2296,7 @@ _comp_command_offset()
                 done
             else
                 cspec=${cspec#complete}
-                cspec=${cspec%%"$compcmd"}
+                cspec=${cspec%%@("$compcmd"|"'${compcmd//\'/\'\\\'\'}'")}
                 COMPREPLY=($(eval compgen "$cspec" -- '$cur'))
             fi
             break