Documentation: Clarify that dirvish-override-dired-mode is required for M-x dirvish to work

[jaeyeom]

Summary

The README states:

After installation, activate Dirvish globally with M-x dirvish-override-dired-mode RET.

This phrasing suggests the mode is optional for "global activation." However, testing shows that M-x dirvish does not work correctly without enabling dirvish-override-dired-mode first.

Steps to Reproduce

1. Start Emacs with emacs -Q
2. Install and load dirvish:

   (require 'package)
   (setq package-archives '(("melpa" . "https://melpa.org/packages/")))
   (package-initialize)
   (package-refresh-contents)
   (package-install 'dirvish)
   (require 'dirvish)

3. Call M-x dirvish

Expected Behavior

A dirvish session opens with preview pane and dirvish features.

Actual Behavior

A plain dired buffer opens. Running M-x dirvish-layout-toggle shows "Not a dirvish buffer".

After Enabling Override Mode

After running M-x dirvish-override-dired-mode, calling M-x dirvish works correctly and opens a proper dirvish session.

Suggestion

Update the documentation to clarify that dirvish-override-dired-mode is required for dirvish to function, not just for "global activation." For example:

After installation, enable dirvish with M-x dirvish-override-dired-mode RET. This is required for dirvish commands to work properly.

Or in use-package:

(use-package dirvish
  :init
  (dirvish-override-dired-mode))  ; Required for dirvish to work

Environment

• Emacs 30.2
• Dirvish (latest from MELPA)
• Tested with emacs -Q (no user config)