Custom templates for documentation nodes

Every documentation node has the same underlying structure, but they serve different purposes; for instance, there are nodes that

• document methods
• document classes
• provide overviews
• serve as the landing page for a package
• are a tutorial

Because of these different uses, there should be different templates according to a node's purpose. Right now (from what I can tell), all nodes extract the SimpleDoc information and display in the order defined in getBody in help.m2: Headline, "Synopsis", Description, SourceCode, Acknowledgement, Contributors, References, Caveat, SeeAlso, Subnodes, "WaysToUse". In this setup, "WaysToUse" serves as the dumping ground for any additional documentation via documentationValue. So, as an example, the authors of a package will always be listed below the description (if one is provided) of the package.

A hacky workaround is to just use documentationValue directly to structure the page after detecting the type of node passed into getBody (see #4408 for an example of this). Presumably, a better system could exist for templating documentation nodes depending on their use-case (also mentioned as a TODO in help.m2).

Start in M2/Macaulay2/m2/help.m2, reading getBody, documentationValue, and the templating TODO, then review issue #4408 for the current workaround. Define how documentation node purposes map to templates and verify that each node type renders its intended sections without relying on WaysToUse as a catch-all.