Add multi-select suggester option

[Giuliano1993]

While using templater i would like to have the possibility to add multiple items when using the suggested call.

For example, I have a template for my social posts, and I usually add some tags or arguments to search the meta fields.
So I would add a boolean parameter to the suggested; when true, the user can select multiple options

[Zachatoo]

There's several duplicates of this same issue (#1130 for example)

[sujyotraut]

I have submitted PR #1149 for this, you can try that out and let me know if it needs improvements.