refactor(completion): name path arguments explicitly and share firstArg

The six commands that take a file or directory argument set their
completer directly instead of a Use-line parser wrapping every
command, the first-argument-only wrappers become one firstArg helper,
and only the bash completion help keeps a custom text.

Signed-off-by: bircni <bircni@icloud.com>

internal/app/action_values.go

@@ -433,10 +433,5 @@ func (a *application) completeActionValues(secret bool, scope *actionScopeFlags)
 	if secret {
 		names = a.completeSecrets(scope.scope)
 	}
-	return func(cmd *cobra.Command, args []string, toComplete string) ([]cobra.Completion, cobra.ShellCompDirective) {
-		if len(args) > 0 {
-			return nil, cobra.ShellCompDirectiveNoFileComp
-		}
-		return names(cmd, args, toComplete)
-	}
+	return firstArg(names)
 }