[SourceKit/CodeFormat] Get 'trailing' indentation to work in more places and fix a bug where multi-line string indentation was modified.

E.g. if/guard condition patterns are column-aligned, but hitting enter after
the ',' below wasn't column-aligning the next empty line:

guard let x = Optional(42),
// No indentation added here after enter

Also the isTargetContext() check takes a start and end token location, but
wasn't accounting for the end location pointing a multiline string, so we
weren't walking into such nodes. This meant we didn't realise the target
location was within a multiline string in some cases, and we ended up
interfering with whitespace in its content.

Author: Nathan Hawes

lib/IDE/Formatting.cpp

@@ -5,4 +5,4 @@ func foo() {
     ) in
 
 // RUN: %sourcekitd-test -req=format -line=6 -length=1 %s | %FileCheck --strict-whitespace %s
-// CHECK: key.sourcetext: "        "
+// CHECK: key.sourcetext: "        "

test/SourceKit/CodeFormat/indent-trailing/trailing-closure-in.swift

@@ -0,0 +1,5 @@
+enum Foo {
+    case a,
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "         "

test/SourceKit/CodeFormat/indent-trailing/trailing-enum-case-comma.swift

@@ -0,0 +1,5 @@
+enum Foo {
+    case
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "        "

test/SourceKit/CodeFormat/indent-trailing/trailing-enum-case-empty.swift

@@ -0,0 +1,5 @@
+enum Foo {
+    case a
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "    "

test/SourceKit/CodeFormat/indent-trailing/trailing-enum-case-no-comma.swift

@@ -0,0 +1,4 @@
+struct Foo<T: Equatable,
+           
+// RUN: %sourcekitd-test -req=format -line=2 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "           "

test/SourceKit/CodeFormat/indent-trailing/trailing-generic-param-comma.swift

@@ -0,0 +1,4 @@
+struct Foo<T: Equatable
+
+// RUN: %sourcekitd-test -req=format -line=2 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: ""

test/SourceKit/CodeFormat/indent-trailing/trailing-generic-param-no-comma.swift

@@ -2,4 +2,4 @@ func foo(x: Bool) {
     guard let number = patterns.index(where: {
 
 // RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
-// CHECK: key.sourcetext: "        "
+// CHECK: key.sourcetext: "        "

test/SourceKit/CodeFormat/indent-trailing/trailing-guard-condition.swift

@@ -0,0 +1,5 @@
+func foo(x: Bool) {
+    guard let number = Optional(23),
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "          "

test/SourceKit/CodeFormat/indent-trailing/trailing-guard-pattern-comma.swift

@@ -0,0 +1,5 @@
+func foo(x: Bool) {
+    guard
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "        "

test/SourceKit/CodeFormat/indent-trailing/trailing-guard-pattern-empty.swift

@@ -0,0 +1,5 @@
+func foo(x: Bool) {
+    guard let number = Optional(23)
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "    "

test/SourceKit/CodeFormat/indent-trailing/trailing-guard-pattern-no-comma.swift

@@ -0,0 +1,5 @@
+func foo(x: Bool) {
+    if let number = Optional(23),
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "       "

test/SourceKit/CodeFormat/indent-trailing/trailing-if-pattern-comma.swift

@@ -0,0 +1,5 @@
+func foo(x: Bool) {
+    if
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "        "

test/SourceKit/CodeFormat/indent-trailing/trailing-if-pattern-empty.swift

@@ -0,0 +1,5 @@
+func foo(x: Bool) {
+    if let number = Optional(23)
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "    "

test/SourceKit/CodeFormat/indent-trailing/trailing-if-pattern-no-comma.swift

@@ -0,0 +1,4 @@
+struct Foo: Equatable,
+
+// RUN: %sourcekitd-test -req=format -line=2 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "            "

test/SourceKit/CodeFormat/indent-trailing/trailing-inherits-item-comma.swift

@@ -0,0 +1,4 @@
+struct Foo: Equatable
+
+// RUN: %sourcekitd-test -req=format -line=2 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: ""

test/SourceKit/CodeFormat/indent-trailing/trailing-inherits-item-no-comma.swift

@@ -0,0 +1,5 @@
+class Foo {
+    func foo(x: Int,
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "             "

test/SourceKit/CodeFormat/indent-trailing/trailing-parameter-list-comma.swift

@@ -0,0 +1,5 @@
+class Foo {
+    func foo(
+        
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "        "

test/SourceKit/CodeFormat/indent-trailing/trailing-parameter-list-empty.swift

@@ -0,0 +1,6 @@
+class Foo {
+    func foo(x: Int
+    
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "    "

test/SourceKit/CodeFormat/indent-trailing/trailing-parameter-list-no-comma.swift

@@ -0,0 +1,4 @@
+public let x = 10,
+
+// RUN: %sourcekitd-test -req=format -line=2 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "           "

test/SourceKit/CodeFormat/indent-trailing/trailing-pattern-binding-decl-comma.swift

@@ -0,0 +1,4 @@
+public let x = 10
+
+// RUN: %sourcekitd-test -req=format -line=2 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: ""

test/SourceKit/CodeFormat/indent-trailing/trailing-pattern-binding-decl-no-comma.swift

@@ -0,0 +1,5 @@
+func foo(x: Bool) {
+    while let number = Optional(23),
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "          "

test/SourceKit/CodeFormat/indent-trailing/trailing-while-pattern-comma.swift

@@ -0,0 +1,5 @@
+func foo(x: Bool) {
+    while
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "        "

test/SourceKit/CodeFormat/indent-trailing/trailing-while-pattern-empty.swift

@@ -0,0 +1,5 @@
+func foo(x: Bool) {
+    while let number = Optional(23)
+
+// RUN: %sourcekitd-test -req=format -line=3 -length=1 %s | %FileCheck --strict-whitespace %s
+// CHECK: key.sourcetext: "    "

test/SourceKit/CodeFormat/indent-trailing/trailing-while-pattern-no-comma.swift

@@ -308,6 +308,14 @@ let s = """
             c
     """
 
+func wantsToIndentContents() {
+    let dontLetItIndentMyValue = """
+a
+    b
+        c
+"""
+}
+
 print("""
     foo {
         bar()