Synopsis: write_ref( self, context, labelname, targetContext=None )
Create a reference to label labelname in the module as given by targetContext. labelname can be expected to be unique within the same context. The targetContext is planned to be used in a (not yet implemented) longref tag for references to labels in other contexts. If this is None than use context as qualificator.
Parameter context is an instance of class FormattingContext describing the current context of the documentation.
If modname is not None , this modname is used as qualificator for the referred label. Otherwise, FormattingContext.moduleName( ) is used.