Switch to spotless and format code (#1196)

* Add spotless configuration

* Reformat!

* Add copyright config for build.gradle.kts files

* Add toeholds for headers

examples/src/main/java/com/squareup/moshi/recipes/CustomQualifier.java

@@ -15,6 +15,8 @@
  */
 package com.squareup.moshi.recipes;
 
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
 import com.squareup.moshi.FromJson;
 import com.squareup.moshi.JsonAdapter;
 import com.squareup.moshi.JsonQualifier;
@@ -22,20 +24,17 @@ import com.squareup.moshi.Moshi;
 import com.squareup.moshi.ToJson;
 import java.lang.annotation.Retention;
 
-import static java.lang.annotation.RetentionPolicy.RUNTIME;
-
 public final class CustomQualifier {
   public void run() throws Exception {
-    String json = ""
-        + "{\n"
-        + "  \"color\": \"#ff0000\",\n"
-        + "  \"height\": 768,\n"
-        + "  \"width\": 1024\n"
-        + "}\n";
+    String json =
+        ""
+            + "{\n"
+            + "  \"color\": \"#ff0000\",\n"
+            + "  \"height\": 768,\n"
+            + "  \"width\": 1024\n"
+            + "}\n";
 
-    Moshi moshi = new Moshi.Builder()
-        .add(new ColorAdapter())
-        .build();
+    Moshi moshi = new Moshi.Builder().add(new ColorAdapter()).build();
     JsonAdapter<Rectangle> jsonAdapter = moshi.adapter(Rectangle.class);
 
     Rectangle rectangle = jsonAdapter.fromJson(json);
@@ -51,22 +50,25 @@ public final class CustomQualifier {
     int height;
     @HexColor int color;
 
-    @Override public String toString() {
+    @Override
+    public String toString() {
       return String.format("%dx%d #%06x", width, height, color);
     }
   }
 
   @Retention(RUNTIME)
   @JsonQualifier
-  public @interface HexColor {
-  }
+  public @interface HexColor {}
 
   static class ColorAdapter {
-    @ToJson String toJson(@HexColor int rgb) {
+    @ToJson
+    String toJson(@HexColor int rgb) {
       return String.format("#%06x", rgb);
     }
 
-    @FromJson @HexColor int fromJson(String rgb) {
+    @FromJson
+    @HexColor
+    int fromJson(String rgb) {
       return Integer.parseInt(rgb.substring(1), 16);
     }
   }