ECL Language Ref Edits: LOOP

The resolution for JIRA ticket 14125 added some additional clarity on what the correct syntax is for form 5 of Loop. Please take a look at the syntax guide and example for form 4.

Form 4 is using what we now know is a row filter from form 5. That's going to confuse folks who look at the syntax guide. It confused me when I wondered if it was a simple transpose issue in the syntax guide (before we had clarity from Gavin).

You might take a look at forms 1 - 3 briefly before we close this ticket to make sure there aren't any other issues.