docs: add `package-info.java` and `readme.md`

(for `klimt/sprite`)

src/net/sourceforge/plantuml/klimt/sprite/package-info.java

@@ -0,0 +1,10 @@
+/**
+ * Provides classes used to manage 
+ * <a href="https://plantuml.com/sprite" target="_top">
+ * Sprite</a>.
+ *
+ * @see net.sourceforge.plantuml.klimt.sprite.CommandListSprite
+ * @see net.sourceforge.plantuml.klimt.sprite.CommandStdlib
+ * 
+ */
+package net.sourceforge.plantuml.klimt.sprite;

src/net/sourceforge/plantuml/klimt/sprite/readme.md

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+# Directory Documentation for `sprite`
+
+## Description
+This package provides classes used to manage [PlantUML Sprite](https://plantuml.com/sprite).
+
+## Link
+- [PlantUML Sprite](https://plantuml.com/sprite)
+
+## Reference
+
+## See also
+- [PlantUML Standard Library](https://plantuml.com/stdlib)
+- [`stdlib`](../../../../../../stdlib/)
+- :octocat: [plantuml/plantuml-stdlib](https://github.com/plantuml/plantuml-stdlib)