Documentation - API Reference

Documented behavior of:
+refs, +log, +show, +archive, +doc, +blame, +diff

Included working endpoints as examples.

References (besides the Gitiles source code):
https://www.chromium.org/developers/change-logs/
https://github.com/google/gitiles/issues/52

Change-Id: Icf3db82574b93be18b61772150baf56f3005b6e3

navbar.md

diff --git a/navbar.md b/navbar.md
index 9f8ac26..0e69e90 100644
--- a/navbar.md
+++ b/navbar.md
@@ -2,5 +2,6 @@
 * [Markdown](/Documentation/markdown.md)
 * [Configuration](/Documentation/config.md)
 * [Developers](/Documentation/developer-guide.md)
+* [API Reference](/Documentation/api-reference.md)
 
 [extensions]: blocknote, multicolumn, namedanchor, smartquote, toc