Modify English document

docs/en/Configuration_System.md

-# ** The system configuration** #
+#  The system configuration #
 
 This section focuses on the configuration of the system (JVM/OS)
 
@@ -22,7 +22,7 @@ As for garbage collection, G1 collector with JDK 1.8 is recommended:
     -XX:G1ReservePercent=25
     -XX:InitiatingHeapOccupancyPercent=30
 
-These GC options looks a little aggressive, but it’s proved to have good performance in our production environment
+These GC options looks a little aggressive, but it’s proved to have good performance in our production environment.
 
 Don’t set a too small value for -XX:MaxGCPauseMillis, otherwise JVM will use a small young generation to achieve this goal which will cause very frequent minor GC.So use rolling GC log file is recommended: