Mark 4.0.0 as released (#23390)

Update changelog and emscripten-version.txt

Author: emscripten-bot

ChangeLog.md

@@ -18,8 +18,11 @@ to browse the changes between the tags.
 
 See docs/process.md for more on how version tagging works.
 
-4.0.0 (in development)
+4.0.1 (in development)
 ----------------------
+
+4.0.0 - 01/14/25
+----------------
 - Emscripten version was bumped to 4.0.0. Happy new year, happy new major
   version!  While version has a few interesting changes, there is nothing huge
   that makes it different from any other release. (#19053)

emscripten-version.txt

@@ -1 +1 @@
-4.0.0-git
+4.0.1-git