[DOCS]: Listbox / Combobox anchor max height

[pablocdev]

Hi!

I have not found in the documentation a way to limit the max height of the options container, for both the listbox and the combobox components.

Using the developer tools, I discovered the --anchor-max-height variable without a value, and tried to use it the same as the --anchor-gap variable and... it works!

I think it would be a good idea to include this in the documentation for both components.

Thanks in advance