Fix multiline function signature parsing

Multiline function signatures with type annotations were incorrectly
parsed as tuples instead of calls when newlines appeared between
parentheses. For example:

```julia
function (
    ::A
)()
end
```

was parsed as `(function (tuple ...) (block))` instead of the correct
`(function (call (parens ...)) (block))`, inconsistent with the
single-line version `function (::A)() end`.

The issue was in parse_function_signature where `peek(ps, 2)` was used
to detect if a call pattern follows the closing parenthesis, but this
didn't skip newlines. Changed to `peek(ps, 2, skip_newlines=true)` to
properly detect the opening parenthesis of the argument list even when
separated by whitespace.

🤖 Generated with [Claude Code](https://claude.ai/code)

Author: KristofferC

src/julia/parser.jl

@@ -2197,7 +2197,15 @@ function parse_function_signature(ps::ParseState, is_function::Bool)
             is_empty_tuple = peek(ps, skip_newlines=true) == K")"
             opts = parse_brackets(ps, K")") do had_commas, had_splat, num_semis, num_subexprs
                 _parsed_call = was_eventually_call(ps)
-                _needs_parse_call = peek(ps, 2) ∈ KSet"( ."
+                # Check if we should skip newlines - only for specific cases
+                # where we have a single type annotation like (::T)
+                _skip_newlines = !had_commas && num_subexprs == 1 && 
+                                !had_splat && num_semis == 0
+                _needs_parse_call = if _skip_newlines
+                    peek(ps, 2, skip_newlines=true) ∈ KSet"( ."
+                else
+                    peek(ps, 2) ∈ KSet"( ."
+                end
                 _is_anon_func = (!_needs_parse_call && !_parsed_call) || had_commas
                 return (needs_parameters = _is_anon_func,
                         is_anon_func     = _is_anon_func,

test/parser.jl

@@ -617,6 +617,11 @@ tests = [
         "function (::g(x))() end" => "(function (call (parens (::-pre (call g x)))) (block))"
         "function (f::T{g(i)})() end" => "(function (call (parens (::-i f (curly T (call g i))))) (block))"
         "function (::T)() end" =>  "(function (call (parens (::-pre T))) (block))"
+        "function (\n        ::T\n        )() end" =>  "(function (call (parens (::-pre T))) (block))"
+        "function (\n        x::T\n        )() end" =>  "(function (call (parens (::-i x T))) (block))"
+        "function (\n        ::T\n        )(x, y) end" =>  "(function (call (parens (::-pre T)) x y) (block))"
+        "function (\n        f::T{g(i)}\n        )() end" => "(function (call (parens (::-i f (curly T (call g i))))) (block))"
+        "function (\n        x, y\n        ) x + y end" => "(function (tuple-p x y) (block (call-i x + y)))"
         "function (:*=(f))() end" => "(function (call (parens (call (quote-: *=) f))) (block))"
         "function begin() end" =>  "(function (call (error begin)) (block))"
         "function f() end"     =>  "(function (call f) (block))"