docs(everywhere): update CLI command

6c0b7e1 introduced a new convention for CLIs defined by Doom's modules:
to namespace them under `doom +MODULE ...`. What was once 'doom
everywhere' is now 'doom +everywhere', so the docs needed correcting.

Ref: 6c0b7e1530

modules/app/everywhere/README.org

@@ -39,8 +39,8 @@ This module requires:
 * Usage
 To use this, invoke the =emacs-everywhere= executable. This can be done in two
 ways:
-+ ~$ emacsclient --eval "(emacs-everywhere)"~
-+ ~$ doom everywhere~
+- ~$ emacsclient --eval "(emacs-everywhere)"~
+- ~$ doom +everywhere~
 
 It is recommended that you add a keybinding for this.