DOC: Fix rst markup in RELEASE_WALKTHROUGH.

doc/RELEASE_WALKTHROUGH.rst.txt

@@ -171,21 +171,21 @@ Reset the maintenance branch into a development state
 -----------------------------------------------------
 
 Add another ``REL`` commit to the numpy maintenance branch, which resets the
-``ISREALEASED`` flag to ``False`` and increments the version counter.:
+``ISREALEASED`` flag to ``False`` and increments the version counter::
 
     $ gvim pavement.py setup.py
 
-Create release notes for next release and edit them to set the version.:
+Create release notes for next release and edit them to set the version::
 
     $ cp doc/release/template.rst doc/release/1.14.6-notes.rst
     $ gvim doc/release/1.14.6-notes.rst
     $ git add doc/release/1.14.6-notes.rst
 
-Add new release notes to the documentation release list.:
+Add new release notes to the documentation release list::
 
     $ gvim doc/source/release.rst
 
-Commit the result.:
+Commit the result::
 
     $ git commit -a -m"REL: prepare 1.14.x for further development"
     $ git push upstream maintenance/1.14.x
@@ -195,7 +195,9 @@ Upload to PyPI
 --------------
 
 Upload to PyPI using ``twine``. A recent version of ``twine`` of is needed
-after recent PyPI changes, version ``1.11.0`` was used here.:
+after recent PyPI changes, version ``1.11.0`` was used here.
+
+.. code-block:: sh
 
     $ cd ../numpy
     $ twine upload release/installers/*.whl