fixed a little problem with changing devices when initialized our device config as duplex; fixed typos

The idea behind this is to avoid subtle bugs that are a result of
accidentally not using atomic operations to reference variables that
must always be used atomically.

This commit does not convert every atomic variable to the new system,
however going forward this will need to be adopted over time.

Public issue https://github.com/mackron/miniaudio/issues/572

Public issue https://github.com/mackron/miniaudio/issues/572

Public issue https://github.com/mackron/miniaudio/issues/572

Public issue https://github.com/mackron/miniaudio/issues/569

Issue from raylib: https://github.com/raysan5/raylib/issues/2118

This reverts commit 0788be81.

This change was technically incorrect. Reverting this change for now
until a better fix is in place. Likely this will require an extra
parameter for controlling this.

Public issue https://github.com/mackron/miniaudio/issues/567

In certain environments (WebWorkers for instance) `window` is undefined. Accessing it will lead to an `Uncaught ReferenceError` that can't be handled by the calling C code. That's why I added a check that will return 0 in such case.

Public issue https://github.com/mackron/miniaudio/issues/550

Public issue https://github.com/mackron/miniaudio/issues/550

This reverts commit f9492ecf.

Public issue https://github.com/mackron/miniaudio/discussions/547