Add "Strict Search" Option for Exact Keymap Filtering

It would be very useful to add a "Strict Search" option to the Keymap search in the preferences section. When enabled, this would filter results to only show keymaps that exactly match the specified key and modifiers, preventing loose matches that include the key with other modifiers.

When disabled, the search would behave as it currently does, showing all keymaps containing the entered key, which is helpful if the user doesn’t remember the full shortcut combination. This toggle would allow both precise filtering and flexible discovery, improving usability for users customizing or migrating keymaps.

Currently the only workaround is described here: blender.stackexchange.com/q/288855/142292