This question is off-topic because it is about a trivial syntax error.
On what criteria do we base syntax, or anything else, being trivial? Your knowledge, or mine, or the number of same/similar previous questions?
None of these could easily be known.
This is a Q&A site, and people are asking because they do not know something which others do.
So under what circumstances should we flag "trivial" when person A doesn't understand X, and person B does?
The main issue is the close reason you propose is it's a bit too specific, and there are potentially hundreds of other new off-topic reasons that could be added in the same vein, ie:
- Doesn't understand basic concept of arrays;
This is why it's tricky getting a good balance for flags between specific reasons that caters for specific scenarios, and generic reasons that cater for multiple scenarios within the specifics.
"trivial" doesn't describe it correctly either. In terms of trying to appoint a new appropriate flag for your example question, it's a case where an answer can easily be found by searching Stack, Google or many other sources quite easily.
Which leads to the suggestions of:
I disagree with the suggestions that your example could come under "minimal understanding". They might have understood perfectly well their code, it might be very complex and highly advanced code, but the issue was a basic knowledge of errors.
Which is why the "minimal understanding of your code" flag is not suitable here.
While it seems Mods and high rep users manning the flags allow leeway and action flags with common sense/logic based on the tools we have, this does leave it open for personal interpretation. As the flag is not logical here, by using it we are "hoping" a mod or high rep users understand our logic and agrees.
A potential to waste of everyone's time.
If someone is asking for a fix on their code it can be argued they are essentially "asking for code" - ie the code that fixes it, but the counter argument is they might be asking for "their code to be fixed" and no need for additional code. This question's example is a perfect example of that.
As with a lot of flags, it's only clear cut when you know specifically how it's used, and not immediately logical to anyone for the first time of seeing it.
For these reasons, plenty of users on MSO have argued that some/most/all the flags should have a revamp of wording, description and purpose.
But I digress..
The suggestions to use "other", while might be correct, the use of this Other flag as a fall back is far from ideal. For us having to write something each time and those reviewing it having to read it and evaluate what we meant etc.
In the specific example you gave "Parse error: syntax error, unexpected '.'", as you said "Almost daily I see 10's of questions", raising this as a duplicate be appropriate if you could find a similar question.
There will likely be a dupe of nearly all these basic errors, or at least one with similar enough logic that the answers describe the resolve to same/similar issues.
Would be to revamp the entire flag system to cater for new scenarios which have come about since the flags were created.
However back to this question... a new flag of:
This question is too basic for this site. While Stack Overflow's purpose is to assist people with their questions, they have no place on Stack Overflow when the answers can very easily be sought by a simple search either here or other sources.
Trouble is, as simple as change this would be for devs, the million+ users are familiar with how it all is now. Change can have adverse effects and of course there is always worry that fixing something that isn't really broken and works "ok" can bring about serious issues.