Update .editorconfig (#2749)

.editorconfig

@@ -1,9 +1,14 @@
+# editorconfig.org
+
 root = true
 
 [*]
 charset = utf-8
 end_of_line = lf
-insert_final_newline = true
-indent_style = space
 indent_size = 2
+indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true
 
+[*.md]
+trim_trailing_whitespace = false