Add template helper documentation

[aldeed]

We should think about a good way to support generating docs for template/UI helpers. Maybe we can use a custom tag or just an @alias.

[raix]

@aldeed Should it work on eg. Template.foo.helpers({}); or/and global helpers?

{{bar name=""}}
Set in "Template.foo" scope

• It should know if its a global helper or scoped
• We have to find a way to support named/unnamed arguments (a helper could support both)
• Know if its a helper or block-helper {{foo}} or {{>foo}}

if I get this correctly?

[aldeed]

Yep, could be tricky. :)

[aldeed]

cc: @aaronjudd