Explicitly call out global naure of ID_TO_TEXTURE map

manimlib/utils/shaders.py

@@ -21,6 +21,7 @@
     from moderngl.framebuffer import Framebuffer
 
 
+# Global maps updated as textures are allocated
 ID_TO_TEXTURE: dict[int, moderngl.Texture] = dict()
 PROGRAM_UNIFORM_MIRRORS: dict[int, dict[str, float | tuple]] = dict()