Add Python 3 modules, and more Python 2 modules.

Also, sort names alphabetically and add module docstrings.

python3/_json.py

@@ -0,0 +1,10 @@
+"""Stub file for the '_json' module."""
+# This is an autogenerated file. It serves as a starting point
+# for a more percise manual annotation of this module.
+# Feel free to edit the source below, but remove this header when you do.
+
+def encode_basestring_ascii(*args, **kwargs) -> object:
+    raise TypeError()
+
+def scanstring(a, b: int, *args, **kwargs) -> tuple:
+    raise TypeError()