[TIDOC-1954] Fix Alloy elements not appearing in docs

To test, patch the` doctools/deploy.sh` script to use the python script, then run the deploy script.

Change line 167 from:
~~~
node ${TI_DOCS}/docgen.js -f jsduck -o ./build ${TI_DOCS} $module_dirs
~~~
to:
~~~
python ${TI_DOCS}/docgen.py -f jsduck -o ./build ${TI_DOCS} $module_dirs
~~~