docs: Annotated Window, MuxTabObj and SpawnCommand.

[DrKJeff16]

Changes

• fix(objects): Completed SpawnCommand.
• fix: Annotated Window and MuxTabObj objects.

[DrKJeff16]

Big Changes

Annotation syntax modifications aside, I fixed many return values for the
Color object: a127caf

@justinsgithub You were using { a: type, b: type, ... } returns instead of tuples:

-- WRONG
---@type fun(): { f: number, oo: boolean }
local function foo()
  -- ...
  return f, oo
end

-- CORRECT
---@type fun(): b: number, a: boolean, r: table
local function bar()
  -- ...
  return b, a, r
end