refactor: rename DTree to DValue

site/doc/pages/is_list.txt

@@ -1,24 +1,24 @@
 :sig
-bool DTree::is_list() const
+bool DValue::is_list() const
 
 :params
 return value : true when the node is a sequential, numerically indexed container
 
 :see
 >types
-0_DTree
+0_DValue
 is_array
 push
 each
-dtree_values
+dv_values
 
 :content
-Tests whether a map-shaped `DTree` represents a list: its keys are the numeric strings `"0"`, `"1"`, `"2"`, ... in unbroken sequence. This is a read accessor: it is `const`, never creates or modifies nodes, and dereferences internal references automatically.
+Tests whether a map-shaped `DValue` represents a list: its keys are the numeric strings `"0"`, `"1"`, `"2"`, ... in unbroken sequence. This is a read accessor: it is `const`, never creates or modifies nodes, and dereferences internal references automatically.
 
 Containers built with `push()` are lists. An empty container counts as a list when it was created with `set_array()` or `push()`; a keyed map (or a map with gaps in its numeric keys) is `is_array()` but not `is_list()`.
 
 ```cpp
-DTree items;
+DValue items;
 items.push(first_item);
 items.push(second_item);
 // items.is_list() == true
@@ -27,7 +27,7 @@ items["custom"] = "x";
 // items.is_list() == false, items.is_array() == true
 ```
 
-`dtree_map()` and `dtree_filter()` use this distinction to decide whether results re-index from zero or keep their original keys.
+`dv_map()` and `dv_filter()` use this distinction to decide whether results re-index from zero or keep their original keys.
 
 ## Related Concepts