Style: Set clang-format Standard to Cpp11

For us, it practically only changes the fact that `A<A<int>>` is now
used instead of the C++03 compatible `A<A<int> >`.

Note: clang-format 10+ changed the `Standard` arguments to fully
specified `c++11`, `c++14`, etc. versions, but we can't use `c++17`
now if we want to preserve compatibility with clang-format 8 and 9.
`Cpp11` is still supported as deprecated alias for `Latest`.

scene/resources/default_theme/default_theme.cpp

@@ -38,7 +38,7 @@
 #include "font_hidpi.inc"
 #include "font_lodpi.inc"
 
-typedef Map<const void *, Ref<ImageTexture> > TexCacheMap;
+typedef Map<const void *, Ref<ImageTexture>> TexCacheMap;
 
 static TexCacheMap *tex_cache;
 static float scale = 1;