Add further details to ROW SHARE table level lock modes section

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/14/explicit-locking.html
Description:

The ROW SHARE table level lock modes section currently states:
```
Conflicts with the EXCLUSIVE and ACCESS EXCLUSIVE lock modes.

The SELECT FOR UPDATE and SELECT FOR SHARE commands acquire a lock of this
mode on the target table(s) (in addition to ACCESS SHARE locks on any other
tables that are referenced but not selected FOR UPDATE/FOR SHARE).
```
I propose that it would be useful to explicitly state that `SELECT FOR KEY
SHARE` AND `SELECT FOR NO KEY UPDATE` commands also acquire the ROW SHARE
table level lock on target table(s). That is:
```
Conflicts with the EXCLUSIVE and ACCESS EXCLUSIVE lock modes.

The SELECT FOR UPDATE, SELECT FOR NO KEY UPDATE, SELECT FOR SHARE, and
SELECT FOR KEY SHARE commands acquire a lock of this mode on the target
table(s) (in addition to ACCESS SHARE locks on any other tables that are
referenced but not selected FOR UPDATE/FOR SHARE).
```

Thank you for your time.