Document import/include outside of top level semantics (#13548)

doc/manual.rst

@@ -5645,6 +5645,8 @@ It is not checked that the ``except`` list is really exported from the module.
 This feature allows to compile against an older version of the module that
 does not export these identifiers.
 
+The ``import`` statement is only allowed at the top level.
+
 
 Include statement
 ~~~~~~~~~~~~~~~~~
@@ -5655,6 +5657,18 @@ statement is useful to split up a large module into several files:
 .. code-block:: nim
   include fileA, fileB, fileC
 
+The ``include`` statement can be used outside of the top level, as such:
+
+.. code-block:: nim
+  # Module A
+  echo "Hello World!"
+
+.. code-block:: nim
+  # Module B
+  proc main() =
+    include A
+  
+  main() # => Hello World!
 
 
 Module names in imports