http2: fix typos in core.js

lib/internal/http2/core.js

@@ -1291,7 +1291,7 @@ class Http2Session extends EventEmitter {
   }
 
   // If ping is called while we are still connecting, or after close() has
-  // been called, the ping callback will be invoked immediately will a ping
+  // been called, the ping callback will be invoked immediately with a ping
   // cancelled error and a duration of 0.0.
   ping(payload, callback) {
     if (this.destroyed)
@@ -1422,7 +1422,7 @@ class Http2Session extends EventEmitter {
     settingsFn();
   }
 
-  // Sumits a GOAWAY frame to be sent to the remote peer. Note that this
+  // Submits a GOAWAY frame to be sent to the remote peer. Note that this
   // is only a notification, and does not affect the usable state of the
   // session with the notable exception that new incoming streams will
   // be rejected automatically.