insertBefore now correctly updates references (#1531)

Removes some workarounds for misplacing the reference when using `insertBefore`.

components/prism-core.js

@@ -138,14 +138,17 @@ var _ = _self.Prism = {
 				}
 			}
 
+			var old = root[inside];
+			root[inside] = ret;
+
 			// Update references in other language definitions
 			_.languages.DFS(_.languages, function(key, value) {
-				if (value === root[inside] && key != inside) {
+				if (value === old && key != inside) {
 					this[key] = ret;
 				}
 			});
 
-			return root[inside] = ret;
+			return ret;
 		},
 
 		// Traverse a language definition with Depth First Search

components/prism-javascript.js

@@ -32,14 +32,13 @@ Prism.languages.insertBefore('javascript', 'string', {
 						pattern: /^\${|}$/,
 						alias: 'punctuation'
 					},
-					rest: null // See below
+					rest: Prism.languages.javascript
 				}
 			},
 			'string': /[\s\S]+/
 		}
 	}
 });
-Prism.languages.javascript['template-string'].inside['interpolation'].inside.rest = Prism.languages.javascript;
 
 if (Prism.languages.markup) {
 	Prism.languages.insertBefore('markup', 'tag', {

components/prism-php.js

@@ -51,6 +51,14 @@
 		}
 	});
 
+	var string_interpolation = {
+		pattern: /{\$(?:{(?:{[^{}]+}|[^{}]+)}|[^{}])+}|(^|[^\\{])\$+(?:\w+(?:\[.+?]|->\w+)*)/,
+		lookbehind: true,
+		inside: {
+			rest: Prism.languages.php
+		}
+	};
+
 	Prism.languages.insertBefore('php', 'string', {
 		'nowdoc-string': {
 			pattern: /<<<'([^']+)'(?:\r\n?|\n)(?:.*(?:\r\n?|\n))*?\1;/,
@@ -78,7 +86,7 @@
 						'punctuation': /^<<<"?|[";]$/
 					}
 				},
-				'interpolation': null // See below
+				'interpolation': string_interpolation // See below
 			}
 		},
 		'single-quoted-string': {
@@ -91,23 +99,13 @@
 			greedy: true,
 			alias: 'string',
 			inside: {
-				'interpolation': null // See below
+				'interpolation': string_interpolation // See below
 			}
 		}
 	});
 	// The different types of PHP strings "replace" the C-like standard string
 	delete Prism.languages.php['string'];
 
-	var string_interpolation = {
-		pattern: /{\$(?:{(?:{[^{}]+}|[^{}]+)}|[^{}])+}|(^|[^\\{])\$+(?:\w+(?:\[.+?]|->\w+)*)/,
-		lookbehind: true,
-		inside: {
-			rest: Prism.languages.php
-		}
-	};
-	Prism.languages.php['heredoc-string'].inside['interpolation'] = string_interpolation;
-	Prism.languages.php['double-quoted-string'].inside['interpolation'] = string_interpolation;
-
 	Prism.hooks.add('before-tokenize', function(env) {
 		if (!/(?:<\?php|<\?)/ig.test(env.code)) {
 			return;