ignore node_modules for docs/modules

Although it is not necessary to run `npm install` in the docs/modules
submodule repos to make and use code or documentation changes, one might
still run `npm install` in order to run the tests for that submodule.

Author: leoj3n

package.json

@@ -57,7 +57,8 @@
         "**/*_test.js",
         "**/test_*.js",
         "**/test-*.md",
-        "**/test.js"
+        "**/test.js",
+        "**/node_modules/**/*"
       ]
     },
     "parent": "BitDocs",