Application can reset stream or close connection even if no error occ…

…urs. (#3953)

* Application can reset stream or close connection even if no error occurs.

The application may reset a stream, for example, when a browser tab is
closed or when the pushed resource is found in cache.  It might close
the connection when the application is closed.  These are not errors per
se, even though the term "stream error" and "connection error" is used
for these events, and they have an associated "error code".

* Update draft-ietf-quic-http.md

Co-authored-by: Mike Bishop <mbishop@evequefou.be>

* Jana's suggestion to pluralize errors.

* Jana's suggestion to pluralize even more

Co-authored-by: Jana Iyengar <jri.ietf@gmail.com>

* Mike's wording of "indicate a problem"

Co-authored-by: Mike Bishop <mbishop@evequefou.be>

Co-authored-by: Bence Béky <bnc@google.com>
Co-authored-by: Mike Bishop <mbishop@evequefou.be>
Co-authored-by: Jana Iyengar <jri.ietf@gmail.com>

draft-ietf-quic-http.md

@@ -1596,9 +1596,11 @@ sent, and receipt MAY be treated as an error of type H3_FRAME_UNEXPECTED.
 # Error Handling {#errors}
 
 QUIC allows the application to abruptly terminate (reset) individual streams or
-the entire connection when an error is encountered.  These are referred to as
-"stream errors" or "connection errors" and are described in more detail in
-{{QUIC-TRANSPORT}}.
+the entire connection; see Sections 2.4 and 5.3 of {{QUIC-TRANSPORT}}.  These
+are referred to as "stream errors" or "connection errors" (see Section 11 of
+{{QUIC-TRANSPORT}}) and have associated error codes, but do not necessarily
+indicate a problem with the connection or either implementation.  For example, a
+stream can be reset if the requested resource is no longer needed.
 
 An endpoint MAY choose to treat a stream error as a connection error under
 certain circumstances.  Implementations need to consider the impact on