Update git submodules

* Update docs/submodules/doctor from branch 'master'
  - fix building docs

    Change-Id: Ie9d07f5a039e43f6468cabb41c610fd642e4c825
    Signed-off-by: Tomi Juvonen <tomi.juvonen@nokia.com>

diff --git a/docs/submodules/doctor b/docs/submodules/doctor
index 2ca5924..5b3f593 160000 (submodule)
--- a/docs/submodules/doctor
+++ b/docs/submodules/doctor
@@ -1 +1 @@
-Subproject commit 2ca5924081ce4784f599437707bd32807aa155ce
+Subproject commit 5b3f5937e7b861fca46b2a6b2d6708866b800f95