HPCC-11624 Document ecl run exceptionLevel option

Signed-off-by: JamesDeFabia <James.Defabia@LexisNexis.com>
Merge pull request #6031 from JamesDeFabia/11624DocExceptionLevel_ecl_run

HPCC-11624 Document ecl run exceptionLevel option

Reviewed-By: Anthony Fishbeck <anthony.fishbeck@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>