REL: Update master after 1.20.0 release.

.mailmap

@@ -55,6 +55,7 @@ Ben Nathanson <[email protected]> bjnath  <[email protected]>
 Benjamin Root <[email protected]> Ben Root <[email protected]>
 Benjamin Root <[email protected]> weathergod <?@?>
 Bernardt Duvenhage <[email protected]> bduvenhage <[email protected]>
+Bernie Gray <[email protected]> bernie gray <[email protected]>
 Bertrand Lefebvre <[email protected]> bertrand <[email protected]>
 Bertrand Lefebvre <[email protected]> Bertrand <[email protected]>
 Bharat Raghunathan <[email protected]> Bharat123Rox <[email protected]>
@@ -76,6 +77,7 @@ Christoph Gohlke <[email protected]> cgohlke <[email protected]>
 Christoph Gohlke <[email protected]> Christolph Gohlke <[email protected]>
 Chunlin Fang <[email protected]> Qiyu8 <[email protected]>
 Chunlin Fang <[email protected]> qiyu8 <[email protected]>
+Chunlin Fang <[email protected]> qiyu8 <[email protected]>
 Chunlin Fang <[email protected]> Chunlin <[email protected]>
 Colin Snyder <[email protected]> colinsnyder <[email protected]>
 Daniel B Allan <[email protected]> danielballan <[email protected]>
@@ -138,7 +140,8 @@ Jaime Fernandez <[email protected]> Jaime Fernandez <[email protected]>
 Jaime Fernandez <[email protected]> jaimefrio <[email protected]>
 Jaime Fernandez <[email protected]> Jaime <[email protected]>
 Jakob Jakobson <[email protected]> Jakob <[email protected]>
-Jakob Jacobson <[email protected]> jakobjakobson13 <[email protected]>
+Jakob Jakobson <[email protected]> Jakob Jacobson <[email protected]>
+Jakob Jakobson <[email protected]> jakobjakobson13 <[email protected]>
 James Webber <[email protected]> jamestwebber <[email protected]>
 Jarrod Millman <[email protected]> Jarrod Millman <[email protected]>
 Jason Grout <[email protected]> Jason Grout <[email protected]>
@@ -270,6 +273,8 @@ Tim Cera <[email protected]> tim cera <[email protected]>
 Tim Teichmann <[email protected]> tteichmann <[email protected]>
 Tim Teichmann <[email protected]> tteichmann <[email protected]>
 Tirth Patel <[email protected]> tirthasheshpatel <[email protected]>
+Tobias Pitters <[email protected]> CloseChoice <[email protected]>
+Tobias Pitters <[email protected]> <[email protected]>
 Tom Boyd <[email protected]> pezcore <[email protected]>
 Tom Poole <[email protected]> tpoole <[email protected]>
 Tony LaTorre <[email protected]> tlatorre <[email protected]>

doc/RELEASE_WALKTHROUGH.rst.txt

@@ -252,6 +252,10 @@ work::
 
     $ firefox doc/build/merge/index.html
 
+Update the stable link::
+
+    $ ln -sfn 1.19 stable
+
 Once everything seems satisfactory, commit and upload the changes::
 
     $ pushd doc/build/merge