Fix return value of get_ptr for unsigned integers (#4525)

* 🐛 fix return value of get_ptr for unsigned integers

* 📝 update documentation

docs/mkdocs/docs/api/basic_json/get_ref.md

@@ -40,7 +40,7 @@ Constant.
 
 !!! danger "Undefined behavior"
 
-    Writing data to the referee of the result yields an undefined state.
+    The reference becomes invalid if the underlying JSON object changes.
 
 ## Examples
 
@@ -58,6 +58,10 @@ Constant.
     --8<-- "examples/get_ref.output"
     ```
 
+## See also
+
+- [get_ptr()](get_ptr.md) get a pointer value
+
 ## Version history
 
 - Added in version 1.1.0.