doc: fix punctuation issue in async_hooks.md

Move period incorrectly placed outside of parentheses to inside the
parentheses. The parenthetical in this case is a full sentence.

PR-URL: #19364
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Yuta Hiroto <hello@hiroppy.me>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

doc/api/async_hooks.md

@@ -284,7 +284,7 @@ The `TCPSERVERWRAP` is the server which receives the connections.
The `TCPWRAP` is the new connection from the client. When a new
connection is made, the `TCPWrap` instance is immediately constructed. This
happens outside of any JavaScript stack. (An `executionAsyncId()` of `0` means
that it is being executed from C++ with no JavaScript stack above it). With only
that it is being executed from C++ with no JavaScript stack above it.) With only
that information, it would be impossible to link resources together in
terms of what caused them to be created, so `triggerAsyncId` is given the task
of propagating what resource is responsible for the new resource's existence.