Deprecate "null" keybindings more strongly?

[stefanhaller]

@jesseduffield, @karimkhaleel:

We still support null keybindings, but the official way to disable a keybinding is <disabled> now (added in #3060). We did this mainly because it's easier to describe in our JSON schema, but also so that we can get rid of our yaml fork, see #2833.

However, we haven't told users that null is deprecated and that they should change it to <disabled> because it will stop working at some point in the future. Should we do that, and if so, how?

We had a similar discussion about deprecating the old edit configurations, and decided against a warning popup at startup, and instead print a message to the console when quitting. Should we do the same thing here?

[stefanhaller]

Oh wait, we can just migrate their config files for them, and then we can remove the yaml fork immediately, no further deprecation period needed. That's better. PR is here: #3459.

[karimkhaleel]

Oh wait, we can just migrate their config files for them, and then we can remove the yaml fork immediately, no further deprecation period needed. That's better. PR is here: #3459.

Good call!