Revert "man: update for Homebrew/homebrew#40985"

This reverts commit 2cdbc07dd0ed210ff631ba3a79365aff429c1906.

Apologies, I'm an idiot who can't read which files were changed properly.

share/man/man1/brew.1

@@ -224,10 +224,10 @@ To install a newer version of HEAD use \fBbrew rm <foo> && brew install \-\-HEAD
 If \fB\-\-git\fR is passed, Homebrew will create a Git repository, useful for creating patches to the software\.
 .
 .IP "\(bu" 4
-\fBirb [\-\-example]\fR: Enter the interactive Homebrew Ruby shell\.
+\fBirb [\-\-examples]\fR: Enter the interactive Homebrew Ruby shell\.
 .
 .IP
-If \fB\-\-example\fR is passed, several examples will be shown\.
+If \fB\-\-examples\fR is passed, several examples will be shown\.
 .
 .IP "\(bu" 4
 \fBleaves\fR: Show installed formulae that are not dependencies of another installed formula\.