Add formatter rules for kts and misc files

build.gradle

@@ -104,6 +104,13 @@ spotless {
         targetExclude("**/build/", "**/resources/", "plugins/openpgp-api-lib/")
         endWithNewline()
     }
+    kotlinGradle {
+        ktlint(libs.versions.ktlint.get())
+            .setEditorConfigPath("$projectDir/.editorconfig")
+        target("**/*.gradle.kts")
+        targetExclude("**/build/")
+        endWithNewline()
+    }
     format("markdown") {
         prettier()
         target("**/*.md")
@@ -111,6 +118,12 @@ spotless {
         trimTrailingWhitespace()
         endWithNewline()
     }
+    format("misc") {
+        target("**/*.gradle", "**/.gitignore")
+        trimTrailingWhitespace()
+        indentWithSpaces(4)
+        endWithNewline()
+    }
 }
 
 tasks.register('testsOnCi') {