fix: incorrect generation of function signatures with tuple parameters

[f-ell]

Tuple types as function parameters are incorrectly parsed as multiple parameters when generating the function signature. This breaks highlighting for the currently active function parameter.

MWE, generated highlight denoted by <...>:

---@param a [any, any]
---@param b any
function X(a, b) end

X({ 1, 2 }|, 3)
-- expected: function X(<a: [any, any]>, b: any)
-- actual:   function X(<a: [any>, any], b: any)

X({ 1, 2 }, 3|)
-- expected: function X(a: [any, any], <b: any>)
-- actual:   function X(a: [any, <any]>, b: any)

Any square brackets are blindly replaced with _ when generating the signature. This works for array types (e.g. any[], which becomes any__), but breaks when scanning for the next parameter delimiter inside of tuples (e.g. [any, any], which becomes _any, any_). Removing matching brackets via %b[] instead keeps the same behaviour for array types, but blanks out the entire tuple for tuple types (i.e. [any, any] becomes __________).

The only potential problem I see with this approach are dictionaries, which may also contain square brackets. These are substituted before attempting to match square brackets however, so this should not cause any issues.