Error message for missing parentheses on static dispatch call

[fpsvogel]

Resolves #9193

Improves the error message when a static dispatch call with zero arguments is missing empty parentheses.

It may make the most sense to review this PR one commit at a time: two tweaks to the error message are in separate commits, because they involve nontrivial logic that I didn't want to lump into the principal changes in the first commit. These are the two tweaks:

• Making the error message point to the method call without parentheses as the problem region (in the example below, not [1, 2, 3] but .len).
• In the suggested fix, extending the highlighted text to include not only the method name but also the empty parentheses (in the example below, not Use `len`() instead but Use `len()` instead).

The new error message:

Source for the above example:

app [main!] { pf: platform "./platform/main.roc" }

main! = || {
  dbg [1, 2, 3].len
}

The current error message, before these changes:

[jaredramirez]

Overall this approach looks good! Just have one note about performance that needs to be figured out, then this is good to merge!

[jaredramirez]

This approach makes sense to me, but it would be ideal to only pay for checking self.isMethodOnNominalType if the unification fails. Running the check for all record fields could get expensive.

Currently, self.unifyInContext is not set up for that, but I think it's worth exploring if there's a nice way to do set the context on error or something!

[fpsvogel]

Good idea, thanks.

In 5f2dbb6 I made that adjustment in a way that felt a bit fragile, so I did a refactor in the next commit 224432b, but I'm not sure if it's worth the extra LOC, at least for now while there is only one case of this type of error. Do you have a preference between the two?

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