Added coding style modes to SimpleMDE (#3286)

* Added coding style modes to SimpleMDE

* Moved the CodeMirror addon from simplemd to codemirror directory

public/plugins/codemirror-5.17.0/mode/rust/test.js

@@ -0,0 +1,39 @@
+// CodeMirror, copyright (c) by Marijn Haverbeke and others
+// Distributed under an MIT license: http://codemirror.net/LICENSE
+
+(function() {
+  var mode = CodeMirror.getMode({indentUnit: 4}, "rust");
+  function MT(name) {test.mode(name, mode, Array.prototype.slice.call(arguments, 1));}
+
+  MT('integer_test',
+     '[number 123i32]',
+     '[number 123u32]',
+     '[number 123_u32]',
+     '[number 0xff_u8]',
+     '[number 0o70_i16]',
+     '[number 0b1111_1111_1001_0000_i32]',
+     '[number 0usize]');
+
+  MT('float_test',
+     '[number 123.0f64]',
+     '[number 0.1f64]',
+     '[number 0.1f32]',
+     '[number 12E+99_f64]');
+
+  MT('string-literals-test',
+     '[string "foo"]',
+     '[string r"foo"]',
+     '[string "\\"foo\\""]',
+     '[string r#""foo""#]',
+     '[string "foo #\\"# bar"]',
+
+     '[string b"foo"]',
+     '[string br"foo"]',
+     '[string b"\\"foo\\""]',
+     '[string br#""foo""#]',
+     '[string br##"foo #" bar"##]',
+
+     "[string-2 'h']",
+     "[string-2 b'h']");
+
+})();