Document Object#clone

fixes #9930

doc/20-language-reference.md

@@ -805,7 +805,8 @@ Array      | [ "a", "b" ]      | An array.
 Dictionary | { a = 3 }         | A dictionary.
 
 Depending on which libraries are loaded additional types may become available. The `icinga`
-library implements a whole bunch of other types, e.g. Host, Service, CheckCommand, etc.
+library implements a whole bunch of other [object types](6-object-types.md#object-types),
+e.g. Host, Service, CheckCommand, etc.
 
 Each type has an associated type object which describes the type's semantics. These
 type objects are made available using global variables which match the type's name:
@@ -816,9 +817,12 @@ type objects are made available using global variables which match the type's na
 The type object's `prototype` property can be used to find out which methods a certain type
 supports:
 
-    /* This returns: ["find","len","lower","replace","split","substr","to_string","upper"] */
+    /* This returns: ["contains","find","len","lower","replace","reverse","split","substr","to_string","upper"] */
     keys(String.prototype)
 
+Additional documentation on type methods is available in the
+[library reference](21-library-reference.md#library-reference).
+
 ## <a id="reserved-keywords"></a> Reserved Keywords
 
 These keywords are reserved and must not be used as constants or custom attributes.

doc/21-library-reference.md

@@ -508,8 +508,22 @@ Signature:
 
 Returns a copy of the string in reverse order.
 
+## <a id="object-type"></a> Object type
+
+### <a id="object-clone"></a> Object#clone
+
+Signature:
+
+     function clone();
+
+Returns a copy of the object. Note that for object elements which are
+reference values (e.g. objects such as arrays or dictionaries) the entire
+object is recursively copied.
+
 ## <a id="array-type"></a> Array type
 
+Inherits methods from the [object type](21-library-reference.md#object-type).
+
 ### <a id="array-add"></a> Array#add
 
 Signature:
@@ -600,6 +614,10 @@ Signature:
 
 Returns a new array with all elements of the current array in reverse order.
 
+## <a id="dictionary-type"></a> Dictionary type
+
+Inherits methods from the [object type](21-library-reference.md#object-type).
+
 ### <a id="dictionary-shallow-clone"></a> Dictionary#shallow_clone
 
 Signature: