Adjust slugs in docs pages

Author: runjak

docs/pages/apis/cursor.mdx

@@ -1,6 +1,6 @@
 ---
 title: pg.Cursor
-slug: /api/cursor
+slug: /apis/cursor
 ---
 
 A cursor can be used to efficiently read through large result sets without loading the entire result-set into memory ahead of time. It's useful to simulate a 'streaming' style read of data, or exit early from a large result set. The cursor is passed to `client.query` and is dispatched internally in a way very similar to how normal queries are sent, but the API it presents for consuming the result set is different.

docs/pages/apis/result.mdx

@@ -1,6 +1,6 @@
 ---
 title: pg.Result
-slug: /api/result
+slug: /apis/result
 ---
 
 The `pg.Result` shape is returned for every successful query.

docs/pages/apis/types.mdx

@@ -1,6 +1,6 @@
 ---
 title: Types
-slug: /api/types
+slug: /apis/types
 ---
 
 These docs are incomplete, for now please reference [pg-types docs](https://github.com/brianc/node-pg-types).