Allow more characters (like whitespaces and punctuations) for escaped identifiers

[benrimmington]

Backticks might also be required (by the compiler) or optional (for readability) if the SE-0111 regression is fixed.

Extending declaration names for closures

SE-0111 was accepted with a small temporary regression of loosing parameter labels in closures. In an extra commentary to this regression the core team pitched a solution that would be purely additive to the language without being a burden for the type system like pre SE-0111. The solution has to come in two steps: We have to extend the declaration names to allow labels in parentheses for variables, properties and parameters. (The following code snippet does not use , in between labels becau…

One of the further suggestions was for multi-line compound names (with insignificant whitespace).

Extending declaration names for closures

Furthermore I think we also should allow multi-line declaration names when they contain parentheses similar to how we can break down a closure type into multiple line when necessary (for instance in a 80 character line width code base): var operate( first: second: third: fourth: fifth: ): ( SomeType, OtherType, SomeVeryLongNameForAType, YetAnotherType, LastType ) -> Void = ...

If I had to choose, I'd prefer to reserve backticks for closures with compound names.