The default `tiling` and `floating` behavior is preserved and matches
both cases.
Adds a new handler to `remanage_window` on A_I3_FLOATING_WINDOW change.
Mainly in order to `run_assignments`, this makes `for_window [floating]`
directives to work for windows which where initially opened as tiling.
Now, when floating is enabled, `for_window` will trigger correctly. Same
applies to `for_window [tiling]`.
The obvious solution of `run_assignments` after
`floating_{enable,disable}` doesn't work because `run_assignments`
modifies the parser state in src/assignments.c:51.
Fixes#3588
Co-Authored-By: Michael Stapelberg <michael@stapelberg.de>