Fix and update the pull request merge procedure

.travis.yml

@@ -1,5 +1,13 @@
 # .travis.yml -- Travis CI configuration for the MPS
 # $Id$
+
+# Some branches don't need builds.  Add them here to avoid using build
+# resources and unnecessary build messages.  See
+# <https://docs.travis-ci.com/user/customizing-the-build/#safelisting-or-blocklisting-branches>.
+branches:
+  except:
+    - branch/2023-01-07/pull-request-merge-procedure
+
 # See <https://docs.travis-ci.com/user/languages/c/>.
 language: c
 os:

contributing.rst

@@ -1,11 +1,14 @@
+=======================
 Contributing to the MPS
 =======================
+
 We are very happy to receive contributions to the Memory Pool System so
 that we can improve it for everyone.
 
 
 Review
 ------
+
 The MPS is highly engineered and rigorously controlled in order to
 prevent defects.  This approach has lead to an extremely small number of
 bugs in production since its first commercial use in 1997.  There are a
@@ -22,26 +25,19 @@ The style guide in guide.impl.c.format_ contains basic rules for style.
 
 Licensing
 ---------
-Prior to the 2020-05 re-licensing of the MPS under the BSD 2-clause
-license, we required contributors to agree to the following
-contribution agreement, so that we could continue to commercially
-license the MPS and thereby fund future development. We have not yet
-decided what may replace this requirement.
-
-    I grant Ravenbrook Ltd an irrevocable, perpetual, worldwide,
-    non-exclusive licence to do anything with [your contribution] that I
-    would have the right to do. This includes (but is not limited to):
 
-    1. reproducing it and doing any other act that is restricted by
-       copyright;
-
-    2. the right to sublicence to others the code and any derivative
-       work.
-
-A member of Ravenbrook staff may ask you to expressly (in writing) agree.
-You just need to reply with “I agree.”  We apologise for the inconvenience.
+All contributions are deemed to have been made under the same license
+as the material to which the contribution is made, unless you
+expressly state otherwise in your contribution request.  In nearly all
+cases this is the `BSD 2-clause license
+<https://opensource.org/licenses/BSD-2-Clause>`_.  You retain the
+copyright to such contributions.
 
 
 Thank you
 ---------
+
 Finally, thank you for making the MPS more useful to everyone.
+
+.. validated with rst2html -v contributing.rst > /dev/null
+.. end