Add CUDA syntax highlighting

C++ highlighting is a good enough substitute for CUDA.

Release-Notes: skip
Change-Id: Ibb82001e9a681c2b37e32e59b5291c566290d465
(cherry picked from commit 5d4ff02ea8010e8d0fdc7e861b2811790e18f4cc)
diff --git a/resources/com/google/gerrit/server/mime/mime-types.properties b/resources/com/google/gerrit/server/mime/mime-types.properties
index fd2280c..61606de 100644
--- a/resources/com/google/gerrit/server/mime/mime-types.properties
+++ b/resources/com/google/gerrit/server/mime/mime-types.properties
@@ -38,6 +38,7 @@
 cpp = text/x-c++src
 cql = text/x-cassandra
 cxx = text/x-c++src
+cu = text/x-c++src
 cyp = application/x-cypher-query
 cypher = application/x-cypher-query
 c++ = text/x-c++src