chore: Add 'H' option to 'cmake build -L' for additional hints (!52)

Use -LH option for cmake build to get additional hints on the cached variables

$ cmake --help
...
-L[A][H]                     = List non-advanced cached variables.
...

Thanks goes to Henry Schreiner for the reminder of this.

* Use `-LH` option for `cmake build` to get additional hints on the cached variables