arbitary -> arbitrary

Author: github-john-doe

src/services/shims.ts

@@ -102,7 +102,7 @@ namespace ts {
         readDirectory(rootDir: string, extension: string, basePaths?: string, excludeEx?: string, includeFileEx?: string, includeDirEx?: string, depth?: number): string;
 
         /**
-         * Read arbitary text files on disk, i.e. when resolution procedure needs the content of 'package.json' to determine location of bundled typings for node modules
+         * Read arbitrary text files on disk, i.e. when resolution procedure needs the content of 'package.json' to determine location of bundled typings for node modules
          */
         readFile(fileName: string): string | undefined;
         realpath?(path: string): string;