Clean up docs issues

The Sphinx build produces a number of warnings and errors. Some are
rightfully ignored, but many need to be fixed. These are mostly
unindexed pages and misformatted references.

Signed-off-by: Eric Ball <eball@linuxfoundation.org>
Change-Id: I9d7a116dc87083ad2dcab20e31cd479364f298cd
diff --git a/howto/code/voltha-protos.rst b/howto/code/voltha-protos.rst
index 3dfa20a..17aca59 100644
--- a/howto/code/voltha-protos.rst
+++ b/howto/code/voltha-protos.rst
@@ -88,7 +88,7 @@
      - Cleanup syntax issues in golang source that will fail your pending commit
    * - go mod vendor
      - | Update sources and dependencies beneath the vendor/ directory.
-       | See also `go-mod-vendor <https://go.dev/ref/mod#go-mod-vendor>`_, `Packages & Modules <https://golangbyexample.com/packages-modules-go-second/>`_
+       | See also `go-mod-vendor <https://go.dev/ref/mod#go-mod-vendor>`_, `Packages & Modules <https://golangbot.com/go-packages/>`_
    * - make build
      - Compile with updated module dependencies.
    * - make test