Replace some common index based for loops with for-of loops

Replaces many loops of the form:

```js
for (let i = 0; i < elements.length; ++i) {
    const i = elements[i];
   ...
}
```

with:

```js
for (const element of elements) {
    ...
}
```

Mix of a horrible regex based find/replace and manual touch ups

extensions/emmet/src/abbreviationActions.ts

@@ -105,9 +105,9 @@ function doWrapping(individualLines: boolean, args: any) {
 
 	function revertPreview(): Thenable<any> {
 		return editor.edit(builder => {
-			for (let i = 0; i < rangesToReplace.length; i++) {
-				builder.replace(rangesToReplace[i].previewRange, rangesToReplace[i].originalContent);
-				rangesToReplace[i].previewRange = rangesToReplace[i].originalRange;
+			for (const rangeToReplace of rangesToReplace) {
+				builder.replace(rangeToReplace.previewRange, rangeToReplace.originalContent);
+				rangeToReplace.previewRange = rangeToReplace.originalRange;
 			}
 		}, { undoStopBefore: false, undoStopAfter: false });
 	}

extensions/emmet/src/reflectCssValue.ts

@@ -29,9 +29,9 @@ function updateCSSNode(editor: TextEditor, property: Property): Thenable<boolean
 	let currentPrefix = '';
 
 	// Find vendor prefix of given property node
-	for (let i = 0; i < vendorPrefixes.length; i++) {
-		if (property.name.startsWith(vendorPrefixes[i])) {
-			currentPrefix = vendorPrefixes[i];
+	for (const prefix of vendorPrefixes) {
+		if (property.name.startsWith(prefix)) {
+			currentPrefix = prefix;
 			break;
 		}
 	}

extensions/emmet/src/selectItemHTML.ts

@@ -119,9 +119,7 @@ function getNextAttribute(selectionStart: vscode.Position, selectionEnd: vscode.
 		return;
 	}
 
-	for (let i = 0; i < node.attributes.length; i++) {
-		let attr = node.attributes[i];
-
+	for (const attr of node.attributes) {
 		if (selectionEnd.isBefore(attr.start)) {
 			// select full attr
 			return new vscode.Selection(attr.start, attr.end);

extensions/emmet/src/toggleComment.ts

@@ -39,8 +39,7 @@ export function toggleComment(): Thenable<boolean> | undefined {
 			return result === 0 ? arr1[0].range.start.character - arr2[0].range.start.character : result;
 		});
 		let lastEditPosition = new vscode.Position(0, 0);
-		for (let i = 0; i < allEdits.length; i++) {
-			const edits = allEdits[i];
+		for (const edits of allEdits) {
 			if (edits[0].range.end.isAfterOrEqual(lastEditPosition)) {
 				edits.forEach(x => {
 					editBuilder.replace(x.range, x.newText);
@@ -151,8 +150,8 @@ function toggleCommentStylesheet(selection: vscode.Selection, rootNode: Styleshe
 }
 
 function adjustStartNodeCss(node: Node | null, pos: vscode.Position, rootNode: Stylesheet): vscode.Position {
-	for (let i = 0; i < rootNode.comments.length; i++) {
-		let commentRange = new vscode.Range(rootNode.comments[i].start, rootNode.comments[i].end);
+	for (const comment of rootNode.comments) {
+		let commentRange = new vscode.Range(comment.start, comment.end);
 		if (commentRange.contains(pos)) {
 			return pos;
 		}
@@ -184,8 +183,8 @@ function adjustStartNodeCss(node: Node | null, pos: vscode.Position, rootNode: S
 }
 
 function adjustEndNodeCss(node: Node | null, pos: vscode.Position, rootNode: Stylesheet): vscode.Position {
-	for (let i = 0; i < rootNode.comments.length; i++) {
-		let commentRange = new vscode.Range(rootNode.comments[i].start, rootNode.comments[i].end);
+	for (const comment of rootNode.comments) {
+		let commentRange = new vscode.Range(comment.start, comment.end);
 		if (commentRange.contains(pos)) {
 			return pos;
 		}