The summary of auto-detected features prints a boolean for every option
to tell the user whether or not the feature has been auto-enabled or
not. This summary can be improved though, as in some cases this boolean
is derived from a dependency. So if we pass in the dependency directly,
then Meson knows to both print a boolean and, if the dependency was
found, it also prints a version number.
Adapt the code accordingly and enable `bool_yn` so that actual booleans
are formatted similarly to dependencies. Before this change: