Add documentation type for a documentation entry.

src/main/java/org/nwapw/abacus/function/DocumentationType.java

@@ -0,0 +1,7 @@
+package org.nwapw.abacus.function;
+
+public enum DocumentationType {
+
+    FUNCTION
+
+}

src/main/kotlin/org/nwapw/abacus/function/Documentation.kt

@@ -10,6 +10,8 @@ package org.nwapw.abacus.function
  * @param name the name of the function in English.
  * @param description the short description of this function.
  * @param longDescription the full description of this function.
+ * @param type the things this documentation maps to.
  */
 data class Documentation(val codeName: String, val name: String,
-                         val description: String, val longDescription: String)
+                         val description: String, val longDescription: String,
+                         val type: DocumentationType)