update command extensions

_mods/command_extensions.md

@@ -0,0 +1,21 @@
+---
+pyproject_url: https://raw.githubusercontent.com/apple1417/willow2-sdk-mods/master/command_extensions/pyproject.toml
+---
+# Command Extensions
+Adds a few new console commands, and provides functionality for other mods to do the same. All these
+commands are fully compatible with blcmm files, you can just put them in your mod and have users
+merge it with other files and enable/disable various categories and it all just keeps working fine.
+
+[See here for info on the builtin commands and how to write mods using them.](Writing-Mods.md)
+
+### Coop Support
+Coop support largely depends on the exact mod making use of this. Command Extensions itself runs
+completely client slide, but specific mods may have more in depth requirements. Some commands are
+simply incompatible with multiplayer, so anything relying on them too much will not work. Like
+always, it's best practice to make sure all players run the exact same set of mods.
+
+### Why does it take longer to `exec` my mods now?
+This mod has to look through your mod file to handle the extra commands. This has to be done before
+the game looks through it, which just takes some extra, unavoidable, time. You can speed it up by
+making your mod file smaller - enable structural edits then delete any categories you don't have
+enabled (and won't suddenly re-enable soon).