Bring the reference/ section back

pradyunsg · pradyunsg · commit 2ae532ac191c · 2021-09-08T08:05:55.000+01:00
This was originally the reference to the command line interface for pip.
That is now handled by cli/ pages, which frees up these pages for
describing other aspects of pip.
diff --git a/docs/html/index.md b/docs/html/index.md
@@ -14,6 +14,7 @@ getting-started
 installation
 user_guide
 topics/index
+reference/index
 cli/index
 ```
 
diff --git a/docs/html/reference/index.md b/docs/html/reference/index.md
@@ -0,0 +1,8 @@
+# Reference
+
+Reference provides information about various file formats, interfaces and
+interoperability standards that pip utilises/implements.
+
+```{toctree}
+
+```
diff --git a/docs/html/reference/index.rst b/docs/html/reference/index.rst
