At some point during the implementation of rename, we added logic for
invalidating the rename state when the selection moved outside the original
rename range. After transitioning to displaying renames as a block decoration,
we don't need that anymore given that a new, temporary editor is used instead.

This commit removes that invalidation logic and always calls `Editor::take_rename`
when the editor selections change. Doing so also fixes a bug that was causing Zed
to hide the cursor when clicking on the editor to dismiss the rename.