Persist options to user.yaml on api->set_option

[rocka]

Is your feature request related to a problem? Please describe.
N/A

Describe the solution you'd like
Persist options to user.yaml when changing option via api->set_option, like #736

Describe alternatives you've considered
N/A

Additional context
fcitx5-rime has a menu to change options via api->set_option, but the options would reset after a maunal sync/deploy. Meanwhile changing options via keyboard shortcut would persist.

[lotem]

The set_option API function provides access to the internal Context::set_option for library users. It's a programming interface. Saving user preference is a higher level functionality. Not every option in Context is saved; nor should the API function set_option case any side effects other than setting the value in the memory of Context.

Value saved in user.yaml should reflect user's preference; selecting an item in the "Input Schema Switcher" menu does exactly that. In contrast, set_option does not correspond to user's action; it could be set by the program itself.

In that sense, this feature request is not the same change as #736, which only changes the timing for saving user selected schema.

[rocka]

If "selecting an item in the 'Input Schema Switcher' menu" reflects user's preference, I wonder why "changing an option in 'options' menu" does not? The option menu is located just below the schema menu, and the schema menu remembers it's previous state. User would expect the option menu to remember its state as well.

[rocka]

Closing this since we have patched librime in fcitx5-android/prebuilder#23