Fix spelling errors in comments and documentation (#7492)

plugins/inputs/graylog/README.md

@@ -7,7 +7,7 @@ Plugin currently support two type of end points:-
 - multiple  (Ex http://[graylog-server-ip]:12900/system/metrics/multiple)
 - namespace (Ex http://[graylog-server-ip]:12900/system/metrics/namespace/{namespace})
 
-End Point can be a mixe of one  multiple end point  and several namespaces end points
+End Point can be a mix of one  multiple end point  and several namespaces end points
 
 
 Note: if namespace end point specified metrics array will be ignored for that call.

plugins/inputs/graylog/graylog.go

@@ -47,7 +47,7 @@ type HTTPClient interface {
 	// req: HTTP request object
 	//
 	// Returns:
-	// http.Response:  HTTP respons object
+	// http.Response:  HTTP response object
 	// error        :  Any error that may have occurred
 	MakeRequest(req *http.Request) (*http.Response, error)