Fix grammar in MultiMesh documentation.

(cherry picked from commit 136567ebcfc584bd218507f44b791b67300b5df6)

doc/classes/MultiMesh.xml

@@ -6,7 +6,7 @@
 	<description>
 		MultiMesh provides low-level mesh instancing. Drawing thousands of [MeshInstance] nodes can be slow, since each object is submitted to the GPU then drawn individually.
 		MultiMesh is much faster as it can draw thousands of instances with a single draw call, resulting in less API overhead.
-		As a drawback, if the instances are too far away of each other, performance may be reduced as every single instance will always render (they are spatially indexed as one, for the whole object).
+		As a drawback, if the instances are too far away from each other, performance may be reduced as every single instance will always render (they are spatially indexed as one, for the whole object).
 		Since instances may have any behavior, the AABB used for visibility must be provided by the user.
 	</description>
 	<tutorials>