Closes#32584
In https://github.com/zed-industries/zed/pull/31888, we changed the
default `opt + shift` behavior to start columnar selection from the
mouse position (Sublime-like behavior) instead of from the existing
selection head (VSCode-like behavior).
It turns out there is a use case for creating columnar selection from an
existing selection head as well, such as creating a consecutive
multi-cursor from existing selection head with just a click instead of
dragging.
This PR brings back columnar selection from the selection head via `opt
+ shift`, while retaining columnar selection from the mouse position,
which is now mapped to the new `cmd + shift` binding.
Note: If you like to swap the binding, you can use [existing multi
cursor modifier
setting](https://zed.dev/docs/configuring-zed?highlight=multi_cursor_modifier#multi-cursor-modifier).
Release Notes:
- Added `cmd + shift` to start columnar selection from the mouse
position.
- Restored `opt + shift` to create columnar selection (or consecutive
multi-cursor on click) from the selection head.