Use spotless to check the style of non-java files (#59)

Author: AustinShalit

build.gradle.kts

@@ -39,6 +39,19 @@ spotless {
     kotlinGradle {
         // Configure the formatting of the Gradle Kotlin DSL files (*.gradle.kts)
         ktlint("0.9.1")
+        trimTrailingWhitespace()
+        indentWithSpaces()
+        endWithNewline()
+    }
+    freshmark {
+        trimTrailingWhitespace()
+        indentWithSpaces()
+        endWithNewline()
+    }
+    format("extraneous") {
+        target("src/**/*.fxml", "src/**/*.css", "*.xml", "*.yml")
+        trimTrailingWhitespace()
+        indentWithSpaces()
         endWithNewline()
     }
 }

src/main/resources/edu/wpi/first/outlineviewer/styles.css

@@ -59,4 +59,4 @@
 .text-field-warning {
     -fx-text-box-border: yellow;
     -fx-focus-color: yellow;
-}
+}