Update file_helper.h

include/spdlog/details/file_helper.h

@@ -6,7 +6,7 @@
 #pragma once
 
 // Helper class for file sinks.
-// When failing to open a file, retry several times(5) with delay interval (10 ms).
+// When failing to open a file, retry several times(5) with a delay interval(10 ms).
 // Throw spdlog_ex exception on errors.
 
 #include "spdlog/details/log_msg.h"