G-7730: Clarify scope

[PhilippSalvisberg]

Based on Connor McDonald's post More triggers are better I've checked the scope of the guideline. Here the results:

✅ ⠀Simple DML trigger (as in Connor's example)
✅ ⠀Compound DML trigger (same code as above in the before each row section)
⛔️ ⠀Instead of Trigger on views (not possible to assign :new values, no locks on the child table)

Maybe it's worth to mention that in the description of the rule.

BTW. Regarding the implementation of this validator check: The check is implemented only partially. I cannot find what's the primary key based on the trigger code (static code analysis without access to Oracle's data dictionary). Therefore I just assume that the primary key is assigned in the trigger. This might lead to false positives when the primary key is not assigned in the trigger code.

[kibeha]

In the fix for #91 I split the old G-7730 - G-7730 is now general rule of trying to avoid multiple DML events in one trigger, while new G-7740 is specific case concerning this child lock behaviour in case of PK assignment (G-7740 being marked as not possible to validate with PL/SQL Cop).
I'll add this scope explanation to G-7740.