try to add html id

doc/MODULE_DESIGN.org

@@ -54,9 +54,11 @@ Not all HPI Modules are currently at that level of complexity -- some are simple
 
 A related concern is [[*An Extendable module structure][how to structure namespace packages]] to allow users to easily extend them, and how this conflicts with single file modules. If a module is converted from a single file module to a namespace with multiple files, it seems this is a breaking change, see [[https://github.com/karlicoss/HPI/issues/89][#89]] for an example of this.
 
+#+html <div id="addingmodules"></div>
+
 * Adding new modules
 
-  As always, if the changes you wish to make are small, or you just want to add a few modules, you can clone and edit an editable install of HPI. See [[file:SETUP.org::*Adding/modifying modules][adding/modifying modules]]
+  As always, if the changes you wish to make are small, or you just want to add a few modules, you can clone and edit an editable install of HPI. See [[file:SETUP.org][SETUP]] for more information
 
   The "proper way" (unless you want to contribute to the upstream) is to create a separate file hierarchy and add your module to =PYTHONPATH=.
 

doc/SETUP.org

@@ -464,4 +464,7 @@ Also check out [[https://beepb00p.xyz/myinfra.html#hpi][my personal infrastructu
 # TODO eh. doesn't even have to be in 'my' namespace?? need to check it
 - The "proper way" (unless you want to contribute to the upstream) is to create a separate file hierarchy and add your module to =PYTHONPATH=.
 
-  See [[file:MODULE_DESIGN.org::*Adding new modules][MODULE_DESIGN/adding modules]] for more information
+# hmmm seems to be no obvious way to link to a header in a separate file,
+# if you want this in both emacs and how github renders org mode
+# https://github.com/karlicoss/HPI/pull/160#issuecomment-817318076
+  See [[file:MODULE_DESIGN.org#addingmodules][MODULE_DESIGN/adding modules]] for more information