fix a typo

docs/manual/buildTools/Testing-with-NPM.html

@@ -106,7 +106,7 @@ $ npm install mocha --save-dev
 				<li>
 					Rerun the test with
 					<code>
-						$ npm test.
+						$ npm test
 					</code>
 
 					This should now succeed, reporting 0 passing (1ms)