Type Hints for Trainer (#912)

* typehints for trainer 

fix type links in docs


fix types in docs


type hints for trainer methods


fix fit docs


switch to comments


readability


added sphinx typehints extension


wip


remove typehints from docstring


more type annotations


fix spaces

* Update trainer.py

Co-authored-by: William Falcon <waf2107@columbia.edu>

docs/source/conf.py

@@ -86,6 +86,7 @@ extensions = [
     'sphinx.ext.autosectionlabel',
     # 'm2r',
     'nbsphinx',
+    'sphinx_autodoc_typehints',
 ]
 
 # Add any paths that contain templates here, relative to this directory.