pw_bloat: Remove .rst from generated size reports

This change removes the .rst extension from the ReST size report files
generated by pw_bloat to prevent Sphinx from checking that they've been
added to a toctree. (Apparently including a file doesn't count as using
it.)

Change-Id: I4edc2db832bac0f370f563ac4f5c68692ad6f85e
diff --git a/pw_bloat/docs.rst b/pw_bloat/docs.rst
index efc16b2..bbbbb48 100644
--- a/pw_bloat/docs.rst
+++ b/pw_bloat/docs.rst
@@ -74,8 +74,8 @@
 Documentation integration
 =========================
 Bloat reports are easy to add to documentation files. All ``pw_size_report``
-targets output a ``.rst`` file containing a tabular report card. This file
-can be imported directly into a documentation file using the ``include``
+targets output a file containing a tabular report card. This file can be
+imported directly into a ReST documentation file using the ``include``
 directive.
 
 For example, the ``simple_bloat_loop`` and ``simple_bloat_function`` size
@@ -85,18 +85,18 @@
 
   Simple bloat loop example
   ^^^^^^^^^^^^^^^^^^^^^^^^^
-  .. include:: examples/simple_bloat_loop.rst
+  .. include:: examples/simple_bloat_loop
 
   Simple bloat function example
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  .. include:: examples/simple_bloat_function.rst
+  .. include:: examples/simple_bloat_function
 
 Resulting in this output:
 
 Simple bloat loop example
 ^^^^^^^^^^^^^^^^^^^^^^^^^
-.. include:: examples/simple_bloat_loop.rst
+.. include:: examples/simple_bloat_loop
 
 Simple bloat function example
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-.. include:: examples/simple_bloat_function.rst
+.. include:: examples/simple_bloat_function