Add more linters to improve code readability (#19989)

Add nakedret, unconvert, wastedassign, stylecheck and nolintlint linters to improve code readability

- nakedret - https://github.com/alexkohler/nakedret - nakedret is a Go static analysis tool to find naked returns in functions greater than a specified function length.
- unconvert - https://github.com/mdempsky/unconvert - Remove unnecessary type conversions
- wastedassign - https://github.com/sanposhiho/wastedassign -  wastedassign finds wasted assignment statements.
- notlintlint -  Reports ill-formed or insufficient nolint directives
- stylecheck - https://staticcheck.io/docs/checks/#ST - keep style consistent
  - excluded: [ST1003 - Poorly chosen identifier](https://staticcheck.io/docs/checks/#ST1003) and [ST1005 - Incorrectly formatted error string](https://staticcheck.io/docs/checks/#ST1005)

modules/graceful/context.go

@@ -26,7 +26,7 @@ func NewChannelContext(done <-chan struct{}, err error) *ChannelContext {
 // Deadline returns the time when work done on behalf of this context
 // should be canceled. There is no Deadline for a ChannelContext
 func (ctx *ChannelContext) Deadline() (deadline time.Time, ok bool) {
-	return
+	return deadline, ok
 }
 
 // Done returns the channel provided at the creation of this context.