Add shortcut to focus roster filter
Problem
If you use single window for roster and chats the only way to start roster filtering is to click on the roster using the mouse and start typing. This is not very intuitive and requires mouse interaction.
Many GUI programs have a shortcut to activate "search" entry. Firefox uses Ctrl+K (if you have search entry available in the toolbar, opens Google otherwise). Thunderbird uses Ctrl+Shift+K to activate quick filter bar. QtCreator uses Ctrl+K to focus the locator (search bar).
Enhancement recommendation
The attached patch adds Ctrl+K shortcut to enable_rfilter with empty filter string and optionally show roster if it was hidden.
The open questions are:
- Is this a desired functionality for base Gajim, or should it go into a plugin (e.g. roster_tweaks).
- Should there be a menuitem (pro: increases discoverability, con: requires translations).
- Currently pressing Ctrl+K will expand the roster tree (as enable_rfilter does it). It may or may not be desired to expand the roster tree until at least one character is input.