editorconfig: remove trailing whitespace in source code

(cherry picked from commit 7c67213cef)

.editorconfig

@@ -7,6 +7,8 @@ root = true
 [*.{c,cg,cpp,gradle,h,java,m,metal,pl,py,S,sh,txt}]
 indent_size = 4
 indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true
 
 [*.{html,js,json,m4,yml,yaml,vcxproj,vcxproj.filters}]
 indent_size = 2