Improve @psalm-internal and prevent usage of IssueBuffer::add().

[AndrolGenhald]

I finally got around to investigating why I'm getting ParseErrors from vendor files, so I decided to make sure stuff like that won't happen again.

• Improve @psalm-internal
  • Allow multiple namespaces/identifiers
  • Allow specifying class names
  • Allow specifying functions and methods
• Make IssueBuffer::add() internal so that it can't be used accidentally.

[AndrolGenhald]

I suppose it might be somewhat debatable whether these ParseErrors should show for vendor files or not, it's a mystery to me why composer is keeping symfony/process installed when it requires PHP >=8.1, but if it were actually used it would crash and Psalm wouldn't notice. On the other hand, it's entirely possible to have some implementations depend on PHP version and conditionally require them, so parsing errors that can never actually show up should definitely not be shown for vendor files.

[orklah]

Looks fine :)

About vendors, I'd say the ideal behaviour would be to crash if we encounter a docblock(or signature) that contains wrong elements (at method level or on class level for templates for example). The rest of the errors are debatable...

The issue is that stubs can make a mess in the flag that says a symbol is from vendors or not (because even if you were able to say the symbol is originally from vendors, what about the symbols within the stubs. Are they vendors too?)

Let me know if it's ready to merge and I'll do it

[AndrolGenhald]

Go ahead 👍

[orklah]

Thanks!