fix(__load_completion): check if cmd is absolute for bin dir

Author: akinomyoga

bash_completion

@@ -2551,7 +2551,7 @@ __load_completion()
     # 3) From bin directories extracted from the specified path to the command,
     # the real path to the command, and $PATH
     paths=()
-    [[ $cmd == */* ]] && paths+=("${cmd%/*}")
+    [[ $cmd == /* ]] && paths+=("${cmd%/*}")
     local ret
     _comp_realcommand "$cmd" && paths+=("${ret%/*}")
     _comp_split -aF : paths "$PATH"