support resolving multiple T into []T

[zzzz465]

Is your feature request related to a problem? Please describe.

when wiring multiple same types, currently I'm forced to create a new type from slice type and write a Provider function manually, like this

type Handlers []types.Handlers

func HandlersProvider() Handlers {
  return []types.Handlers {
    handler.NewHandlerA,
    handler.NewHandlerB,
   ...
}

Describe the solution you'd like

wire.Slice(
  T,
  providers...
)

for example, like this

// this provides multiple T into single T, also this can be defined multiple times, everything will be joined to single type
wire.Slice(
  []types.EventHandler,
  handler.NewHandlerA,
  handler.NewHandlerB,
  handler.NewHandlerC,
  ... // keep going
)

Describe alternatives you've considered

Additional context

I implemented Proof of Concept in my forked branch. see below:
https://github.com/zzzz465/wire/tree/feat/wire-slice