build(docs-infra): display github links in CLI API docs (#26515)

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

aio/tools/transforms/angular-api-package/index.js

@@ -34,6 +34,7 @@ module.exports = new Package('angular-api', [basePackage, typeScriptPackage])
   .processor(require('./processors/removeInjectableConstructors'))
   .processor(require('./processors/processPackages'))
   .processor(require('./processors/processNgModuleDocs'))
+  .processor(require('./processors/fixupRealProjectRelativePath'))
 
 
   /**