[Feature Request] support new keyword `fieldFormats:`

[TenviLi]

when you use template: table, the keyword fields: can't meet the needs of customizing each field

now we can support new keyword fieldFormats:

here is an example:

fieldFormats: ['{index}', '{h1_title}', '{tags}']

So now there is a question, what about the <th> of the table？

now we can support new keyword thFormats:

thFormats: ['hi', 'i\'m', 'the first line']