#296 "Macro" definitions

[Lars Hellström]

In request#1969144, I've described two markup commands [alt] and [rep] that in principle are just combinations of other markup commands with some fixed text arguments, not unlike a macro in e.g. TeX.

Had there been a facility through which manpage writers could define new command on a per-page basis, like LaTeX authors often do in the preambles of documents, then I could just have defined these commands and went ahead and used them, not having to wait for Doctools to be updated with them.

The advantage of defining new "macro" commands for repeated elements, rather than just writing out their expansions in full, is that it provides greater consistency in formatting. It also makes it easy to switch from one notation to another, simply by changing the definition of the custom command which generates that definition.