chore(docs): rename @private to @internal

The latter is understood by TypeScript's --stripInternal option, so this lets us
rely more on the tooling provided by typescript team.

modules/angular2/src/core/compiler/runtime_compiler.ts

@@ -10,7 +10,7 @@ import {Promise, PromiseWrapper} from 'angular2/src/core/facade/async';
 @Injectable()
 export class RuntimeCompiler extends Compiler {
   /**
-   * @private
+   * @internal
    */
   constructor(_protoViewFactory: ProtoViewFactory, private _templateCompiler: TemplateCompiler) {
     super(_protoViewFactory);

modules/angular2/src/core/compiler/url_resolver.ts

@@ -145,7 +145,7 @@ function _buildFromEncodedParts(opt_scheme?: string, opt_userInfo?: string, opt_
  *    $7 = Related           fragment without #
  * </pre>
  * @type {!RegExp}
- * @private
+ * @internal
  */
 var _splitRe =
     RegExpWrapper.create('^' +