Update capped-collections.txt

Removal of 'delete operations' from intro wording since delete operation is not supported in capped collections

Signed-off-by: Sam Kleinman <[email protected]>

Author: mcascallares

source/core/capped-collections.txt

@@ -5,8 +5,8 @@ Capped Collections
 .. default-domain:: mongodb
 
 :term:`Capped collections <capped collection>` are fixed-size
-collections that support high-throughput operations that insert,
-retrieve, and delete documents based on insertion order. Capped
+collections that support high-throughput operations that insert
+and retrieve documents based on insertion order. Capped
 collections work in a way similar to circular buffers: once a
 collection fills its allocated space, it makes room for new documents
 by overwriting the oldest documents in the collection.