This commit includes the following changes:
* CLI version information is read from the CLI package from which
we read the help files.
* CLI API pages now contain GH links
* line numbers are not shown in GH links, if the doc does not
have a truthy `startingLine` value. This allows us to remove
hard coded checks for `guide` pages
* content pages and CLI api docs no longer have a `startingLine`
* the hard-coded `packages` path segment has been removed from
the templates; instead we now only use the `realProjectRelativePath`.
* the `realProjectRelativePath` has been updated accordingly for API
and CLI API docs.
PR Close#26515
This is to tidy up the `author-packagse`, which currently duplicates a
lot of the configuration in the main packages. We need to
DRY this up so that we don't fall foul of a change in one being missed in
the other.