* home-cursor.nix: enable gtk module when enabling gtk config generation
The gtk configurations are not generated unless config.gtk is enabled.
This is a point of confusion because config.home.pointerCursor.gtk can essentially be disabled,
despite having it enabled.
* home-cursor.nix: Add note to gtk config generation description instead of enabling gtk module
* home-cursor.nix: Add note about applying pointerCursor configs to main submodule desc
* home-cursor.nix: Change tabs to spaces
d2e47de536