HPCC-13913 Edits based upon review

Signed-off-by: Jim DeFabia <jamesdefabia@lexisnexis.com>

docs/ECLStandardLibraryReference/SLR-Mods/FromStringToDate.xml

@@ -38,7 +38,8 @@
           <entry>return</entry>
 
           <entry>The date that was matched in the string. Returns 0 if failed
-          to match.</entry>
+          to match or if the date components match but the result is an
+          invalid date.</entry>
         </row>
       </tbody>
     </tgroup>

ecllibrary/std/Date.ecl

@@ -1,4 +1,4 @@
-/*##############################################################################
+/*##############################################################################
 ## HPCC SYSTEMS software Copyright (C) 2012 HPCC Systems.  All rights reserved.
 ############################################################################## */
 
@@ -601,7 +601,8 @@ EXPORT Seconds_t SecondsFromDateTimeRec(DateTime_rec datetime, BOOLEAN is_local_
  * @param date_text     The string to be converted.
  * @param format        The format of the input string.
  *                      (See documentation for strftime)
- * @return              The date that was matched in the string.  Returns 0 if failed to match.
+ * @return              The date that was matched in the string.  Returns 0 if failed to match 
+ *                      or if the date components match but the result is an invalid date.
  *
  * Supported characters:
     %B          Full month name