pw_multibuf: Add missing space to fix docs rendering

Change-Id: Icd4d5debb7f609f395d55b3c35df2c0678d8114b
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/235633
Reviewed-by: Josh Conner <[email protected]>
Pigweed-Auto-Submit: Faraaz Sareshwala <[email protected]>
Reviewed-by: Kayce Basques <[email protected]>
Lint: Lint 🤖 <[email protected]>
Commit-Queue: Faraaz Sareshwala <[email protected]>

pw_multibuf/docs.rst

@@ -51,7 +51,7 @@ Most users of ``pw_multibuf`` will start by allocating a ``MultiBuf`` using
 a ``MultiBufAllocator`` class, such as the ``SimpleAllocator``.
 
 ``MultiBuf`` s consist of a number of ``Chunk`` s of contiguous memory regions.
-``Chunk`` s can be grown or shrunk which allows ``MultiBuf``s to be grown or
+``Chunk`` s can be grown or shrunk which allows ``MultiBuf`` s to be grown or
 shrunk. This allows, for example, lower layers to reserve part of a
 ``MultiBuf`` for a header or footer (see ``Chunk`` for more details).