Improve error message for invalid regex to search

Fixes https://github.com/Homebrew/homebrew/issues/50131



This commit removes the error backtrace and improves the error message
if a bad regexp is passed to `brew search`.

Closes Homebrew/homebrew#50173.

Signed-off-by: Martin Afanasjew <martin@afanasjew.de>

Library/Homebrew/cmd/search.rb

@@ -93,6 +93,8 @@ module Homebrew
     when %r{^/(.*)/$} then Regexp.new($1)
     else /.*#{Regexp.escape(query)}.*/i
     end
+  rescue RegexpError
+    odie "#{query} is not a valid regex"
   end
 
   def search_taps(rx)