Rework pos types, add types for mark utils

[bew]

Extracted from #1396 (and reworked a little)

• Rework position types
• Add types for all Mark utils
• Remove unused Mark:update method (ref)

[L3MON4D3]

I think it should be doable via @overload, but I'm not getting the correct results with this simple example

---@param a number
---@param b number
---@return boolean
---@overload fun(table,table) : boolean
local function test(a, b) return a == b end

test(1,{})

[bew]

could we get this merged ? it's an important one to get the ball rolling ;)