Fix heading/link code stripping; add WIKILINK contexts to documentation.

mwparserfromhell/nodes/heading.py

@@ -45,7 +45,7 @@ class Heading(Node):
             yield self.title, child
 
     def __strip__(self, normalize, collapse):
-        return self.title
+        return self.title.strip_code(normalize, collapse)
 
     def __showtree__(self, write, get, mark):
         write("=" * self.level)

mwparserfromhell/nodes/wikilink.py

@@ -50,8 +50,8 @@ class Wikilink(Node):
 
     def __strip__(self, normalize, collapse):
         if self.text is not None:
-            return self.text
-        return self.title
+            return self.text.strip_code(normalize, collapse)
+        return self.title.strip_code(normalize, collapse)
 
     def __showtree__(self, write, get, mark):
         write("[[")

mwparserfromhell/parser/contexts.py

@@ -46,6 +46,11 @@ Local (stack-specific) contexts:
     * :py:const:`ARGUMENT_NAME`
     * :py:const:`ARGUMENT_DEFAULT`
 
+* :py:const:`WIKILINK`
+
+    * :py:const:`WIKILINK_TITLE`
+    * :py:const:`WIKILINK_TEXT`
+
 * :py:const:`HEADING`
 
     * :py:const:`HEADING_LEVEL_1`