VOL-4840 - docs.voltha.org edits

Makefile
patches/python_310_migration.sh
-------------------------------
   o Change log message to note venv patching by version.
   o Original message could be interpreted as explict patching of wrong version.

makefiles/lint/include.mk
-------------------------
   o Document lint targets: usage, commands, makefiles, etc.

Change-Id: I895a0a032f856632c9adf31aa634b6cbf0328cdb
diff --git a/howto/code/index.rst b/howto/code/index.rst
new file mode 100644
index 0000000..0d23582
--- /dev/null
+++ b/howto/code/index.rst
@@ -0,0 +1,8 @@
+Development & Source Code
+=========================
+
+.. toctree::
+   :maxdepth: 2
+
+   linting
+   pull_request