Expand release procedure instructions on tagging releases

Author: msimberg

docs/release_procedure.rst

@@ -93,7 +93,9 @@ the lines as they are completed to avoid confusion.
     The main CMakeLists.txt contains a comment indicating for which version
     the breaking change was introduced first.
 
-#.  Tag a release candidate from the release branch.
+#.  Tag a release candidate from the release branch, where tag name is the
+    version to be released with a "-rcN" suffix and description is
+    "HPX V$VERSION: The C++ Standards Library for Parallelism and Concurrency".
 
     *   ``git tag -a [tag name] -m '[description]'``
     *   ``git push origin [tag name]``
@@ -142,7 +144,12 @@ the lines as they are completed to avoid confusion.
 #.  Add the release date to the caption of the current "What's New" section in
     the docs.
 
-#.  Tag the release.
+#.  Tag the release from the release branch, where tag name is the version to be
+    released and description is "HPX V$VERSION: The C++ Standards Library for
+    Parallelism and Concurrency".
+
+    *   ``git tag -a [tag name] -m '[description]'``
+    *   ``git push origin [tag name]``
 
 #.  Roll a release candidate using ``tools/roll_release.sh`` (from root directory), and add the
     hashsums generated by the script to the "downloads" page of the website.