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/issues.go

@@ -187,22 +187,10 @@ $ tea issue view https://gitea.com/OWNER/REPO/issues/12 --web`, Annotations: map
 	}}
 	cmd.Flags().BoolVarP(&web, "web", "w", false, "Open the issue in the browser")
 	cmd.Flags().BoolVarP(&comments, "comments", "c", false, "View issue comments")
-	cmd.ValidArgsFunction = a.completeIssueArgs("open", false)
+	cmd.ValidArgsFunction = firstArg(a.completeIssues("open"))
 	return cmd
 }
 
-// completeIssueArgs completes issue numbers in state for the first argument, or for every
-// argument when variadic.
-func (a *application) completeIssueArgs(state string, variadic bool) cobra.CompletionFunc {
-	complete := a.completeIssues(state)
-	return func(cmd *cobra.Command, args []string, toComplete string) ([]cobra.Completion, cobra.ShellCompDirective) {
-		if len(args) > 0 && !variadic {
-			return nil, cobra.ShellCompDirectiveNoFileComp
-		}
-		return complete(cmd, args, toComplete)
-	}
-}
-
 func (a *application) issueCreateCommand() *cobra.Command {
 	var title, body, bodyFile, deadline, templateName, ref, milestone string
 	var useEditor, web bool
@@ -446,7 +434,7 @@ $ tea issue %[1]s 12 13 --comment "Done in #14"`, verb), Annotations: map[string
 		return errors.Join(append(failures, writeBatchJSON(a, cmd, len(numbers), results))...)
 	}}
 	cmd.Flags().StringVarP(&comment, "comment", "c", "", "Leave a comment before the issue is "+state)
-	cmd.ValidArgsFunction = a.completeIssueArgs(completeState, true)
+	cmd.ValidArgsFunction = a.completeIssues(completeState)
 	return cmd
 }