Ability to suppress issues in specific functions or methods via config

[shira-374]

Hello.

I prefer to use <issueHandlers> in Psalm config instead of using the tool-specific @psalm-suppress annotation, but it seems there is no way to limit these only to specific functions or methods.

Some issue types support this via <referencedMethod>, <referencedClass> or <referencedVariable>, but most of them don't.

Maybe something like <method> and <function> could be implemented for all issue types?

<issueHandlers>
  <SomeIssue>
    <errorLevel type="suppress">
      <!-- suppress SomeIssue, but only inside the code or doc-blocks of these methods or functions -->
      <method name="Example\SomeClass::someMethod" />
      <function name="Example\someFunction" />
    </errorLevel>
  </SomeIssue>
</issueHandlers>

What do you think?