pillow fight help doesn't state how to specify collections

Description

the pillowfight help text contains the following regarding targeting a specific collection.

--collection Allowed collection full path including scope (could be specified multiple times) [Default=]

It wasn't obvious that I needed to use `.` to specify the collection (as in `_default.mycollection`).

None

None

None

Show:

Build couchbase-server-7.2.5-7575 contains libcouchbase commit 93ef937 with commit message:
https://couchbasecloud.atlassian.net/browse/CCBC-1584#icft=CCBC-1584: update documentation on how to use collections with pillowfight

Build couchbase-server-7.1.6-3969 contains libcouchbase commit 93ef937 with commit message:
https://couchbasecloud.atlassian.net/browse/CCBC-1584#icft=CCBC-1584: update documentation on how to use collections with pillowfight

Build capella-analytics-1.0.0-1006 contains libcouchbase commit 93ef937 with commit message:
https://couchbasecloud.atlassian.net/browse/CCBC-1584#icft=CCBC-1584: update documentation on how to use collections with pillowfight

Build couchbase-server-7.6.0-1438 contains libcouchbase commit 93ef937 with commit message:
https://couchbasecloud.atlassian.net/browse/CCBC-1584#icft=CCBC-1584: update documentation on how to use collections with pillowfight

Build couchbase-server-8.0.0-1384 contains libcouchbase commit 93ef937 with commit message:
https://couchbasecloud.atlassian.net/browse/CCBC-1584#icft=CCBC-1584: update documentation on how to use collections with pillowfight