CURLOPT_DOH_URL.3: mention the known bug

It is mostly duplicating info from KNOWN_BUGS but make it easier to find
for users of this option.

Closes #8790

docs/libcurl/opts/CURLOPT_DOH_URL.3

@@ -55,6 +55,12 @@ can be controlled separately via \fICURLOPT_DOH_SSL_VERIFYHOST(3)\fP and
 \fICURLOPT_DOH_SSL_VERIFYPEER(3)\fP.
 
 A set \fICURLOPT_OPENSOCKETFUNCTION(3)\fP callback is not inherited.
+.SH "KNOWN BUGS"
+Even when DoH is set to be used with this option, there are still some name
+resolves that are performed without it, using the default name resolver
+mechanism. This includes name resolves done for \fICURLOPT_INTERFACE(3)\fP,
+\fICURLOPT_FTPPORT(3)\fP, a proxy type set to \fBCURLPROXY_SOCKS4\fP or
+\fBCURLPROXY_SOCKS5\fP and probably some more.
 .SH DEFAULT
 NULL - there is no default DoH URL. If this option is not set, libcurl will use
 the default name resolver.
@@ -75,8 +81,8 @@ Added in 7.62.0
 Returns CURLE_OK on success or CURLE_OUT_OF_MEMORY if there was insufficient
 heap space.
 
-Note that \fIcurl_easy_setopt(3)\fP will not actually parse the given string so
-given a bad DoH URL, curl will not detect a problem until it tries to resolve
-a name with it.
+Note that \fIcurl_easy_setopt(3)\fP will not immediately parse the given
+string so when given a bad DoH URL, libcurl might not detect the problem until
+it later tries to resolve a name with it.
 .SH "SEE ALSO"
 .BR CURLOPT_VERBOSE "(3), " CURLOPT_RESOLVE "(3), "