Update java/ql/src/Violations of Best Practice/Undesirable Calls/CallsToSystemExit.ql

Co-authored-by: Michael Nebel <michaelnebel@github.com>

Author: Napalys

java/ql/src/Violations of Best Practice/Undesirable Calls/CallsToSystemExit.ql

@@ -44,7 +44,7 @@ class ExitOrHaltMethodCall extends MethodCall {
 
 /**
  * An intentional `MethodCall` to a system or runtime "exit" method, such as for
- * functions which exist for the purpose of exiting the program. Assumes that a an exit method
+ * functions which exist for the purpose of exiting the program. Assumes that an exit method
  * call within a method is intentional if the exit code is passed from a parameter of the
  * enclosing method.
  */