Add Doxygen as a supported docstringFormat

[mgannprc]

The only change needed would be to add an exclaimation point to the end of the leading triple-quote. Otherwise the templating system works well.

I'm pasting the template I created for doxygen docstrings: ` {{! Doxygen Docstring Template }} {{summaryPlaceholder}}

{{extendedSummaryPlaceholder}}

{{#parametersExist}} {{#args}} @param {{var}} ({{typePlaceholder}}): {{descriptionPlaceholder}} {{/args}} {{#kwargs}} @param {{var}} ({{typePlaceholder}}, optional): {{descriptionPlaceholder}}. Defaults to {{&default}}. {{/kwargs}} {{/parametersExist}}

{{#exceptionsExist}} {{#exceptions}} @exception {{type}}: {{descriptionPlaceholder}} {{/exceptions}} {{/exceptionsExist}}

{{#returnsExist}} {{#returns}} @returns {{typePlaceholder}}: {{descriptionPlaceholder}} {{/returns}} {{/returnsExist}}

{{#yieldsExist}} {{#yields}} @returns {{typePlaceholder}}: {{descriptionPlaceholder}} {{/yields}} {{/yieldsExist}} `