Two documentation updates (#30049)

* `require` takes to arguments
* `jl_new_uniontype` does not exist anymore

(cherry picked from commit ef496b0)

base/loading.jl

@@ -795,7 +795,7 @@ const full_warning_showed = Ref(false)
 const modules_warned_for = Set{PkgId}()
 
 """
-    require(module::Symbol)
+    require(into::Module, module::Symbol)
 
 This function is part of the implementation of `using` / `import`, if a module is not
 already defined in `Main`. It can also be called directly to force reloading a module,

doc/src/devdocs/object.md

@@ -116,7 +116,6 @@ Types:
 ```c
 jl_datatype_t *jl_apply_type(jl_datatype_t *tc, jl_tuple_t *params);
 jl_datatype_t *jl_apply_array_type(jl_datatype_t *type, size_t dim);
-jl_uniontype_t *jl_new_uniontype(jl_tuple_t *types);
 ```
 
 While these are the most commonly used options, there are more low-level constructors too, which