[BasicFormat] Handle some additional cases for self + Self

Author: hamishknight

Sources/SwiftBasicFormat/BasicFormat.swift

@@ -307,7 +307,11 @@ open class BasicFormat: SyntaxRewriter {
       (.keyword(.`init`), .leftAngle),  // init<T>()
       (.keyword(.`init`), .leftParen),  // init()
       (.keyword(.self), .period),  // self.someProperty
-      (.keyword(.Self), .period),  // self.someProperty
+      (.keyword(.self), .leftParen),  // self()
+      (.keyword(.self), .leftSquare),  // self[]
+      (.keyword(.Self), .period),  // Self.someProperty
+      (.keyword(.Self), .leftParen),  // Self()
+      (.keyword(.Self), .leftSquare),  // Self[]
       (.keyword(.set), .leftParen),  // var mVar: Int { set(value) {} }
       (.keyword(.subscript), .leftParen),  // subscript(x: Int)
       (.keyword(.super), .period),  // super.someProperty

Tests/SwiftBasicFormatTest/BasicFormatTests.swift

@@ -190,6 +190,34 @@ final class BasicFormatTest: XCTestCase {
     )
   }
 
+  func testSelfCall1() {
+    assertFormatted(
+      source: "self(0)",
+      expected: "self(0)"
+    )
+  }
+
+  func testSelfCall2() {
+    assertFormatted(
+      source: "Self(0)",
+      expected: "Self(0)"
+    )
+  }
+
+  func testSelfSubscript1() {
+    assertFormatted(
+      source: "self[0]",
+      expected: "self[0]"
+    )
+  }
+
+  func testSelfSubscript2() {
+    assertFormatted(
+      source: "Self[0]",
+      expected: "Self[0]"
+    )
+  }
+
   func testCustomIndentationInBlockThatDoesntHaveNewline() {
     assertFormatted(
       source: """