fix encoding of chars

src/core/ext/transport/chttp2/transport/chttp2_transport.c

@@ -997,7 +997,7 @@ void grpc_chttp2_add_incoming_goaway(grpc_exec_ctx *exec_ctx,
   t->seen_goaway = 1;
 
   /* When a client receives a GOAWAY with error code ENHANCE_YOUR_CALM and debug
-   * data equal to “too_many_pings”, it should log the occurrence at a log level
+   * data equal to "too_many_pings", it should log the occurrence at a log level
    * that is enabled by default and double the configured KEEPALIVE_TIME used
    * for new connections on that channel. */
   if (t->is_client && goaway_error == GRPC_HTTP2_ENHANCE_YOUR_CALM &&

src/core/ext/transport/chttp2/transport/internal.h

@@ -820,7 +820,7 @@ void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
 /** Add a new ping strike to ping_recv_state.ping_strikes. If
     ping_recv_state.ping_strikes > ping_policy.max_ping_strikes, it sends GOAWAY
     with error code ENHANCE_YOUR_CALM and additional debug data resembling
-    “too_many_pings” followed by immediately closing the connection. */
+    "too_many_pings" followed by immediately closing the connection. */
 void grpc_chttp2_add_ping_strike(grpc_exec_ctx *exec_ctx,
                                  grpc_chttp2_transport *t);