Support typed throws

https://github.com/swiftlang/swift-evolution/blob/main/proposals/0413-typed-throws.md

Author: taku0

swift-mode-lexer.el

@@ -614,7 +614,11 @@ return non-nil."
                  "isolated" "each"))
        (member (swift-mode:token:text next-token)
                '("any" "some" "inout" "borrowing" "consuming" "throws"
-                 "rethrows" "in" "where" "isolated" "each")))
+                 "rethrows" "in" "where" "isolated" "each"))
+
+       ;; Suppress implicit semicolon between throws and open parenthesis.
+       (and (equal (swift-mode:token:text previous-token) "throws")
+            (eq (swift-mode:token:type next-token) '\()))
       nil)
 
      ;; Before async

test/swift-files/indent/declarations.swift

@@ -489,6 +489,17 @@ func foo
   ) {
 }
 
+func foo()
+  throws
+  (
+    any
+      Error
+  )
+  ->
+  Int {
+    1
+}
+
 // Enumeration declarations
 
 fileprivate

test/swift-files/indent/statements.swift

@@ -1228,6 +1228,18 @@ catch
     foo()
 }
 
+do
+  throws
+  (
+    any
+      Error
+  ) {
+    foo()
+} catch
+  let
+    e {
+}
+
 // Multi-Pattern Catch Clauses
 // https://github.com/apple/swift-evolution/blob/master/proposals/0276-multi-pattern-catch-clauses.md