Plugin MouseFreeURLHandler fails to extract text and clear search between commands #846

While working on related #835 but I found:

bug - MouseFreeURLHandler was failing to get terminal text

flow - If a user has a few urls on screen and he is searching, it works. But now he runs some more commands and then he gets new urls. If the user pressed <Alt>j to find next, the search was happening only in previous text. So in this change the plugin on finding a <return> resets to search to include full text

A new KeyBindUtil use case was found: TODO separately

For KeyBindUtil if we register then keybinding will be shown in Preferences->Keybindings and if any other plugin
wants to listen to same key code it will throw error since in UI binding has to be unique. May be we can have keybinds
hidden from UI which plugins can use internally for common keys like <Return> <Alt> etc

Test : After applying fix

• Should work normally in searching urls <Alt>j <Alt>k and <Alt><Return>

• Search current urls, Then run any command (this should clear search). Now try to get more URL text on screen. Now search should work for all urls.