Rename references for WinRT to UWP

contributing/bug_triage_guidelines.rst

@@ -88,7 +88,7 @@ unthinkable to see issues that fit two bills. The general idea is that
 there will be specialized contributors teams behind all topics, so they
 can focus on the issues labelled with their team topic.
 
-**Platforms:** *Android*, *HTML5*, *iOS*, *Linux*, *OS X*, *Windows*, *Winrt*
+**Platforms:** *Android*, *HTML5*, *iOS*, *Linux*, *OS X*, *Windows*, *UWP*
 
 By default, it is assumed that a given issue applies to all platforms. 
 If one of the platform labels is used, it is the exclusive and the

reference/introduction_to_the_buildsystem.rst

@@ -215,6 +215,6 @@ create it's own template.
 
 If you are working for multiple platforms, OSX is definitely the best
 host platform for cross compilation, since you can cross-compile for
-almost every target (except for winrt). Linux and Windows come in second
+almost every target (except for UWP). Linux and Windows come in second
 place, but Linux has the advantage of being the easier platform to set
 this up.