Change section titles in docs

CHANGELOG.rst

@@ -1,6 +1,6 @@
-=================
-Changelog history
-=================
+=========
+Changelog
+=========
 
 Versions follow `Semantic Versioning <https://semver.org/>`_ (``<major>.<minor>.<patch>``).
 

doc/en/_templates/globaltoc.html

@@ -4,7 +4,7 @@
   <li><a href="{{ pathto('index') }}">Home</a></li>
   <li><a href="{{ pathto('getting-started') }}">Install</a></li>
   <li><a href="{{ pathto('contents') }}">Contents</a></li>
-  <li><a href="{{ pathto('reference') }}">Reference</a></li>
+  <li><a href="{{ pathto('reference') }}">API Reference</a></li>
   <li><a href="{{ pathto('example/index') }}">Examples</a></li>
   <li><a href="{{ pathto('customize') }}">Customize</a></li>
   <li><a href="{{ pathto('changelog') }}">Changelog</a></li>

doc/en/reference.rst

@@ -1,5 +1,5 @@
-Reference
-=========
+API Reference
+=============
 
 This page contains the full reference to pytest's API.