DOCSP-20021: Update redirects file for 5.2 (#120)

Author: jeff-allen-mongo

config/redirects

@@ -1,5 +1,5 @@
 define: base https://docs.mongodb.com
-define: versions v2.2 v2.4 v2.6 v3.0 v3.2 v3.4 v3.6 v4.0 v4.2 v4.4 v5.0 master
+define: versions v2.2 v2.4 v2.6 v3.0 v3.2 v3.4 v3.6 v4.0 v4.2 v4.4 v5.0 v5.1 master
 symlink: manual -> v5.0
 symlink: upcoming -> v5.0
 symlink: master -> v5.0
@@ -1791,6 +1791,12 @@ raw: /manual/core/wildcard -> ${base}/manual/core/index-wildcard/
 
 [v4.4-*]: /${version}/genindex -> ${base}/${version}/
 
+#
+# Redirects for new 5.2 pages
+#
+
+[v3.6-v5.1]: /${version}/reference/operator/aggregation/locf/ -> ${base}/${version}/reference/operator/aggregation/
+
 #
 # Redirects for new 5.1 pages
 #