Re-enable "Wiki links".

[gmilde]

In Moin 1.9, hyperlink references without target default to items of the local wiki. Port this feature to Moin 2.0.
Adapt to the new program structure:

Define a "transform" that resolves hyperlink references without a matching target.

Define a custom parser to register the "transform". (The Writer component is not used in Moin 2.0)

Call docutils.core.publish_doctree() with the custom parser. Also specify a "source_path" identifier (for improved error messages).

[gmilde]

TODO: Update documentation. How?
Suggestion:

diff --git a/src/moin/help/help-en/rst.data b/src/moin/help/help-en/rst.data
index cee5fd96..26975935 100644
--- a/src/moin/help/help-en/rst.data
+++ b/src/moin/help/help-en/rst.data
@@ -134,11 +134,12 @@ Within the rst syntax:
  * a link that begins with a namespace like ``http:users/Home`` links to the Home item in the target namespace
  * a link like ``http:../sibling`` links to a sibling of the current item
 
-.. _myanchor:
-
 +-----------------------------+-------------------------------------+------------------------------------------------------------+
 |Markup                       |Result                               |Comment                                                     |
 +=============================+=====================================+============================================================+
+| ``link_``                   |link_                                |_`link` to a heading or anchor in this item or an item      |
+|                             |                                     |in the default namespace of this wiki                       |
++-----------------------------+-------------------------------------+------------------------------------------------------------+
 | ``http:Home``               |http:Home                            |link to an item in the default namespace of this wiki       |
 +-----------------------------+-------------------------------------+------------------------------------------------------------+
 | ```Home2 <http:Home>`_``    |`Home2 <http:Home>`_                 |fancy link to an item in the default namespace of this wiki |
@@ -155,14 +156,16 @@ Within the rst syntax:
 +-----------------------------+-------------------------------------+------------------------------------------------------------+
 | ```Internal Links`_``       |`Internal Links`_                    |link to a heading with embedded blanks                      |
 +-----------------------------+-------------------------------------+------------------------------------------------------------+
-| ``.. _myanchor:``           |                                     |create anchor, real anchor is above this table              |
+| ``_`anchor:```              |_`anchor`                            |inline anchor, the id is derived from the text.             |
++-----------------------------+-------------------------------------+------------------------------------------------------------+
+| ``.. _myanchor:``           |.. _myanchor:                        |invisilble anchor for the next (block-level) element        |
 +-----------------------------+-------------------------------------+------------------------------------------------------------+
 | ``myanchor_``               |myanchor_                            |link to above anchor                                        |
 +-----------------------------+-------------------------------------+------------------------------------------------------------+
 
 **Notes:**
  - If this page was created by Sphinx, none of the above internal link examples work correctly.
- - The ".. _myanchor:" directive must begin in column one.
+ - The ".. _myanchor:" directive does not work inline.
  - Section titles (or headings) automatically generate hyperlink targets (the title
    text is used as the hyperlink name).

[gmilde]

This patch is one part of a solution for issue #1680

[RogerHaase]

Thanks for helping!

The rst docs are in docs/user/rest.rst. Edit with your favorite editor, save, run /m docs to update the local docs. Restart the server, view the changes at http://127.0.0.1:5000/help-en/rst

Commit when you are ready.