Comment as to why docs are built against Python 3.6 (#1550)

diff --git a/.travis.yml b/.travis.yml
index e7e8694530ca21a6d7a19da3fab687a3e9d79e9c..2062e81bea9e9dd051c6d481cd5cf77089ce0520 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -32,6 +32,7 @@ matrix:
   include:
     - os: linux
       language: python
+      # Build the docs against a stable version of Python so code bugs don't hold up doc-related PRs.
       python: 3.6
       env:
         - TESTING=docs