docs(ngdoc): ensure module installation docs are accurate

The ngMock module is built into a package called angular-mocks, which is
not named consistently and the docs were giving invalid info.

Closes #5810

docs/src/ngdoc.js

@@ -1401,6 +1401,14 @@ function explainModuleInstallation(moduleName){
     modulePackage = 'angular-' + moduleName,
     modulePackageFile = modulePackage + '.js';
 
+  // Deal with inconsistent ngMock naming - doing it verbosely and explicitly here
+  // rather than cleverly interweaving it in the previous lines to make it obvious
+  // what is going on
+  if ( moduleName == 'mock' ) {
+    modulePackage = 'angular-mocks';
+    modulePackageFile = modulePackage + '.js';
+  }
+
   return '<h1>Installation</h1>' +
     '<p>First include <code>' + modulePackageFile +'</code> in your HTML:</p><pre><code>' +
     '    &lt;script src=&quot;angular.js&quot;&gt;\n' +

src/ngMock/angular-mocks.js

@@ -1729,7 +1729,7 @@ angular.mock.$RootElementProvider = function() {
  * In addition, ngMock also extends various core ng services such that they can be
  * inspected and controlled in a synchronous manner within test code.
  *
- * {@installModule mocks}
+ * {@installModule mock}
  *
  * <div doc-module-components="ngMock"></div>
  *