Fix: '.md' to '.html' with anchors (fixes #1415)

Markdown documentation can now reference another markdown file with an anchor and it will work for the site along with github.
ex. `working-with-rules.md#rule-unit-tests`
Merge pull request #1417 from Nate-Wilkins/patch-1

Fix: '.md' to '.html' with anchors (fixes #1415)
New: Add operator-assignment rule (fixes #1420)
0.9.2
Revert "Fix: '.md' to '.html' with anchors (fixes #1415)"
Merge pull request #1425 from eslint/revert-1417-patch-1

Revert "Fix: '.md' to '.html' with anchors (fixes #1415)"
Merge pull request #1423 from btmills/operator-assignment

New: Add operator-assignment rule (fixes #1420)