Add "emptycase" linter

[leonklingele]

Your feature request related to a problem? Please describe.

The emptycase linter finds case statements with no body.

As per their README:

---

It is common knowledge for gopher that there is no fall through in the switch-case statement of the Go language. However, people who are used to C or Java may inadvertently write code like the following.

func f() {
	v := 1
	switch v {
	case 1:
	case 2:
		fmt.Println("execute")
	}
}

Of course, Println() donesn't be executed. However, it takes a while to realize this when you write it. This Analyzer detects empty cases, making it faster to notice problems.

---

https://github.com/gostaticanalysis/emptycase

Describe the solution you'd like.

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Describe alternatives you've considered.

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Additional context.

No response

[rattuscz]

Any blocker for this one?
Got burned by empty switch case and wanted to find linter for it :-)

[Antonboom]

Looks like part of gocritic. In addition of existing one:

1. https://go-critic.com/overview.html#defaultcaseorder
2. https://go-critic.com/overview.html#caseorder
3. https://go-critic.com/overview.html#dupcase
4. https://go-critic.com/overview.html#emptyfallthrough

Or staticcheck:

1. Flag empty and default-only switch statements dominikh/go-tools#992
2. https://staticcheck.dev/docs/checks/#SA4020
3. https://staticcheck.dev/docs/checks/#ST1015