[2.1.x] Refs #28814 -- Doc'd Python 3.7 compatibility in Django 1.11.x.

Backport of 2fd21a18 from master.

docs/faq/install.txt

@@ -46,7 +46,7 @@ What Python version can I use with Django?
 ============== ===============
 Django version Python versions
 ============== ===============
-1.11           2.7, 3.4, 3.5, 3.6
+1.11           2.7, 3.4, 3.5, 3.6, 3.7 (added in 1.11.17)
 2.0            3.4, 3.5, 3.6, 3.7
 2.1, 2.2       3.5, 3.6, 3.7
 ============== ===============

docs/releases/1.11.17.txt

@@ -4,7 +4,8 @@ Django 1.11.17 release notes
 
 *Release date TBD*
 
-Django 1.11.17 fixes several bugs in 1.11.16.
+Django 1.11.17 fixes several bugs in 1.11.16 and adds compatibility with
+Python 3.7.
 
 Bugfixes
 ========

docs/releases/1.11.txt

@@ -22,9 +22,9 @@ for the previous LTS, Django 1.8, will end in April 2018.
 Python compatibility
 ====================
 
-Django 1.11 requires Python 2.7, 3.4, 3.5, or 3.6. Django 1.11 is the first
-release to support Python 3.6. We **highly recommend** and only officially
-support the latest release of each series.
+Django 1.11 requires Python 2.7, 3.4, 3.5, 3.6, or 3.7 (as of 1.11.17). We
+**highly recommend** and only officially support the latest release of each
+series.
 
 The Django 1.11.x series is the last to support Python 2. The next major
 release, Django 2.0, will only support Python 3.4+.