DOCS-15409 updates Capped Collection size constraints (#2031)

* DOCS-15409 updates Capped Collection size constraints

* internal review feedback

Author: jmd-mongo

source/core/capped-collections.txt

@@ -148,9 +148,8 @@ space for internal overhead.
 
    db.createCollection( "log", { capped: true, size: 100000 } )
 
-If the ``size`` field is less than or equal to 4096, then the collection will
-have a cap of 4096 bytes. Otherwise, MongoDB will raise the provided size to
-make it an integer multiple of 256.
+MongoDB increases the provided ``size`` to make it an integer multiple 
+of 256.
 
 Additionally, you may also specify a maximum number of documents for the
 collection using the ``max`` field as in the following document: