docs: add missing repo API docs link (#3672)

Alan Shaw · web-flow · commit 5eb32a75137f · 2021-05-06T11:48:48.000+01:00
diff --git a/docs/core-api/README.md b/docs/core-api/README.md
@@ -18,5 +18,6 @@ It is broken up into the following sections:
 * [PIN.md](PIN.md)
 * [PUBSUB.md](PUBSUB.md)
 * [REFS.md](REFS.md)
+* [REPO.md](REPO.md)
 * [STATS.md](STATS.md)
 * [SWARM.md](SWARM.md)
