Focus Keybindings search when opened from the command palette or Settings search

[NikitaMGrimm]

Selecting Keybindings through Ctrl+K opens the page, but searching requires another Ctrl+F or a mouse click. Would you approve an XS- or S-sized PR that automatically focuses the search field when someone enters Keybindings? The same would apply when someone selects the Keybindings page through Settings search.

The search field losing focus happens without that change already, so this won't cause any unexpected behavior that doesn't already happen. Pressing Ctrl+F already focuses the Keybindings search, so this would simply remove that extra step and would similarly not cause anything unexpected.

Related: #12822 redesigns the page but doesn't add automatic focus.