C++: Change name of UncheckedReturn...Functions.ql

The previous name was identical to the name of
`Adding365DaysPerYear.ql`. It may have been a copy-paste error.

Author: jbj

cpp/ql/src/Likely Bugs/Leap Year/UncheckedReturnValueForTimeFunctions.ql

@@ -1,5 +1,5 @@
 /**
- * @name Year field changed using an arithmetic operation is used on an unchecked time conversion function
+ * @name Unchecked return value for time conversion function
  * @description A year field changed using an arithmetic operation is used on a time conversion function, but the return value of the function is not checked for success or failure
  * @kind problem
  * @problem.severity warning