Remove stream locking from within io.
Default to unlocked streams.
Remove stream-lock: #f now that streams are unlocked.
Make format-out, force-out thread safe.

As requested in http://bugzilla.opendylan.org/show_bug.cgi?id=4004.
Update release notes for change to stream locking.
[doc,format-out] Update format-out module docs.
[docs,streams] Remove bad usage of with-stream-locked.
Clean up whitespace.
Don't lock stream during format().

This shouldn't be necessary when the application is locking correctly.
Don't lock stream during print().

The application should be handling this as well if the stream is
shared between threads.
Seal lock/unlock-stream where possible.

Add sealed domains for lock-stream and unlock-stream on
<byte-string-stream>, <unicode-string-stream>, and
<simple-wrapper-stream>.
[doc,streams] Document locking management methods.
Merge pull request #621 from dylan-lang/stream-locking-changes

Stream locking changes