doc: use _can_ to describe actions in quic.md

Per Microsoft style guide:

> When ability is what you need to express, it's OK to use _can_ to
> describe actions or tasks that the reader or program is able to do.
> Use _might_ to express possibility. Don't use _may_, which might be
> interpreted as providing permission.

Refs: https://docs.microsoft.com/en-us/style-guide/a-z-word-list-term-collections/c/can-may
Refs: #34353 (comment)

PR-URL: #34613
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>

doc/api/quic.md

@@ -2465,7 +2465,7 @@ start of a new `QuicServerSession`. It is invoked with three arguments:
 * `servername` {string} The SNI server name specified by the client.
 * `ciphers` {string[]} The array of TLS 1.3 ciphers specified by the client.
 
-The `clientHelloHandler` *may* return a new {tls.SecureContext} object that will
+The `clientHelloHandler` can return a new {tls.SecureContext} object that will
 be used to continue the TLS handshake. If the function returns `undefined`, the
 default {tls.SecureContext} will be used. Returning any other value will cause
 an error to be thrown that will destroy the `QuicServerSession` instance.