Remove Spurious Line Start Condition From Closure Signature Effect Parsing

Fixes #725

rdar://99669872

Author: CodaFi

Sources/SwiftParser/Expressions.swift

@@ -1991,7 +1991,6 @@ extension Parser.Lookahead {
   mutating func consumeEffectsSpecifiers() {
     var loopProgress = LoopProgressCondition()
     while self.currentToken.isEffectsSpecifier
-            && !self.currentToken.isAtStartOfLine
             && loopProgress.evaluate(currentToken) {
       self.consumeAnyToken()
     }

Tests/SwiftParserTest/Types.swift

@@ -32,4 +32,12 @@ final class TypeTests: XCTestCase {
       DiagnosticSpec(message: "Unexpected text '..' found in function type")
     ])
   }
+
+  func testClosureSignatures() throws {
+    AssertParse("""
+                { ()
+                throws -> Void in }
+                """,
+                { $0.parseClosureExpression() })
+  }
 }