fix some typos (#314)

Signed-off-by: cuishuang <imcusg@gmail.com>

Author: cuishuang

cmd/grpcurl/grpcurl.go

@@ -109,7 +109,7 @@ var (
 		separator.`))
 	allowUnknownFields = flags.Bool("allow-unknown-fields", false, prettify(`
 		When true, the request contents, if 'json' format is used, allows
-		unkown fields to be present. They will be ignored when parsing
+		unknown fields to be present. They will be ignored when parsing
 		the request.`))
 	connectTimeout = flags.Float64("connect-timeout", 0, prettify(`
 		The maximum time, in seconds, to wait for connection to be established.

format.go

@@ -428,7 +428,7 @@ type DefaultEventHandler struct {
 // the given output. If verbose is true, all events are logged. Otherwise, only
 // response messages are logged.
 //
-// Deprecated: NewDefaultEventHandler exists for compatability.
+// Deprecated: NewDefaultEventHandler exists for compatibility.
 // It doesn't allow fine control over the `VerbosityLevel`
 // and provides only 0 and 1 options (which corresponds to the `verbose` argument).
 // Use DefaultEventHandler{} initializer directly.