Show alternative definitions in glossary?

~15 terms in the glossary have alternative definitions - these are currently not displayed and have typically not been translated. For consistency, maybe we should leave the English ones out? Otherwise, they could be appended to the definition by code. Currently they are in an alternative_definition field in the master sheet that is not used.

Start with the glossary generation or display entry point and trace how the master sheet's alternative_definition field is currently handled. Compare the available alternatives with the rendered glossary and translation data; done should mean the chosen treatment is implemented consistently for all affected terms.

Written by the indexing model from the issue text.