feat: add swift indents (#4756)

tests/indent/swift/statements.swift

@@ -0,0 +1,34 @@
+func Test() {
+  if true {
+    return
+  } else if true {
+    return
+  }
+
+  switch x {
+  case "1":
+    print("x")
+  default:
+    print("y")
+  @unknown default:
+    print("z")
+  }
+
+  for a in b {
+  }
+
+  while true{
+  }
+
+  repeat {
+
+  } while (true)
+
+  guard let name = person["name"] else {
+    return
+  }
+
+  return (
+    x + 1
+  )
+}