Remove duplicate changelog entry

Author: osa1

CHANGELOG.md

@@ -21,17 +21,6 @@
     Instead use: `Matrix4.scaledByDouble`, `Matrix4.scaledByVector3`,
     `Matrix4.scaledByVector4`.
 
-- New `Matrix4` members added with precise argument types (instead of
-  `dynamic`), with better performance:
-  - `Matrix4.scaleByDouble`, `Matrix4.scaleByVector3`, `Matrix4.scaleByVector4`
-    as faster `Matrix4.scale`.
-  - `Matrix4.translateByDouble`, `Matrix4.translateByVector3`,
-    `Matrix4.translateByVector4` as faster `Matrix4.translate`.
-  - `Matrix4.leftTranslateByDouble`, `Matrix4.leftTranslateByVector3`,
-    `Matrix4.leftTranslateByVector4` as faster `Matrix4.leftTranslate`.
-  These new functions should be preferred over the old ones when the argument
-  type is known at a call site.
-
 ## 2.1.5
 
 - Fixed `operator -()` of Quaternion (Contributed by tlserver)