Cleanup left-over line-highlight tags before other plugins run

The tags used by the line-highlight plugin are appended to the <code>
tag. This causes problems with the autoloader plugin, because the
tags contain whitespace and therefore change the content of the <code>
tag.

This patch fixes the issue #1101, by removing any line-highlight tags
with the `before-sanity-check` hook.

plugins/line-highlight/prism-line-highlight.js

@@ -44,12 +44,12 @@ function highlightLines(pre, lines, classes) {
 
 	for (var i=0, range; range = ranges[i++];) {
 		range = range.split('-');
-					
+
 		var start = +range[0],
 		    end = +range[1] || start;
-		
+
 		var line = document.createElement('div');
-		
+
 		line.textContent = Array(end - start + 2).join(' \n');
 		line.setAttribute('aria-hidden', 'true');
 		line.className = (classes || '') + ' line-highlight';
@@ -77,25 +77,25 @@ function highlightLines(pre, lines, classes) {
 
 function applyHash() {
 	var hash = location.hash.slice(1);
-	
+
 	// Remove pre-existing temporary lines
 	$$('.temporary.line-highlight').forEach(function (line) {
 		line.parentNode.removeChild(line);
 	});
-	
+
 	var range = (hash.match(/\.([\d,-]+)$/) || [,''])[1];
-	
+
 	if (!range || document.getElementById(hash)) {
 		return;
 	}
-	
+
 	var id = hash.slice(0, hash.lastIndexOf('.')),
 	    pre = document.getElementById(id);
 
 	if (!pre) {
 		return;
 	}
-	
+
 	if (!pre.hasAttribute('data-line')) {
 		pre.setAttribute('data-line', '');
 	}
@@ -107,22 +107,40 @@ function applyHash() {
 
 var fakeTimer = 0; // Hack to limit the number of times applyHash() runs
 
-Prism.hooks.add('complete', function(env) {
+Prism.hooks.add('before-sanity-check', function(env) {
 	var pre = env.element.parentNode;
 	var lines = pre && pre.getAttribute('data-line');
-	
+
 	if (!pre || !lines || !/pre/i.test(pre.nodeName)) {
 		return;
 	}
-
-	clearTimeout(fakeTimer);
-
+
+	/*
+	 * Cleanup for other plugins (e.g. autoloader).
+	 *
+	 * Sometimes <code> blocks are highlighted multiple times. It is necessary
+	 * to cleanup any left-over tags, because the whitespace inside of the <div>
+	 * tags change the content of the <code> tag.
+	 */
 	$$('.line-highlight', pre).forEach(function (line) {
 		line.parentNode.removeChild(line);
 	});
-
+
+	env.code = env.element.textContent;
+});
+
+Prism.hooks.add('complete', function(env) {
+	var pre = env.element.parentNode;
+	var lines = pre && pre.getAttribute('data-line');
+
+	if (!pre || !lines || !/pre/i.test(pre.nodeName)) {
+		return;
+	}
+
+	clearTimeout(fakeTimer);
+
 	highlightLines(pre, lines);
-	
+
 	fakeTimer = setTimeout(applyHash, 1);
 });