cleanup: general removal of TODO (and similar) comments

They tend to never get updated anyway so they're frequently inaccurate
and we never go back to revisit them anyway. We document issues to work
on properly in KNOWN_BUGS and TODO instead.

lib/http2.c

@@ -75,8 +75,6 @@ static int http2_perform_getsock(const struct connectdata *conn,
   int bitmap = GETSOCK_BLANK;
   (void)numsocks;
 
-  /* TODO We should check underlying socket state if it is SSL socket
-     because of renegotiation. */
   sock[0] = conn->sock[FIRSTSOCKET];
 
   if(nghttp2_session_want_read(c->h2))
@@ -576,8 +574,7 @@ static int on_data_chunk_recv(nghttp2_session *session, uint8_t flags,
 
   /* if we receive data for another handle, wake that up */
   if(conn->data != data_s)
-    Curl_expire(data_s, 1); /* TODO: fix so that this can be set to 0 for
-                               immediately? */
+    Curl_expire(data_s, 1);
 
   DEBUGF(infof(data_s, "%zu data received for stream %u "
                "(%zu left in buffer %p, total %zu)\n",