Describe the bug
revive incorrectly identities channel draining as an empty code block and suggests to remove it.

To Reproduce
Steps to reproduce the behavior:

1. I updated revive go get -u github.com/mgechev/revive
2. I run it with the following flags & configuration file:

cd $PROJECT_DIR
revive -config revive.toml .

ignoreGeneratedHeader = false
severity = "error"
confidence = 0.8
errorCode = 1
warningCode = 0

[rule.add-constant]
    arguments = [{maxLitCount = "3",allowStrs ="\"\"",allowInts="0,1,2"}]
[rule.argument-limit]
    arguments = [6]
[rule.atomic]
[rule.blank-imports]
[rule.bool-literal-in-expr]
[rule.call-to-gc]
[rule.constant-logical-expr]
[rule.context-as-argument]
[rule.context-keys-type]
[rule.cyclomatic]
    arguments = [10]
[rule.deep-exit]
[rule.dot-imports]
[rule.duplicated-imports]
[rule.empty-block]
[rule.error-naming]
[rule.error-return]
[rule.error-strings]
[rule.errorf]
[rule.exported]
[rule.flag-parameter]
[rule.function-result-limit]
    arguments = [4]
[rule.get-return]
[rule.if-return]
[rule.import-shadowing]
[rule.increment-decrement]
[rule.indent-error-flow]
[rule.line-length-limit]
    arguments = [120]
[rule.package-comments]
[rule.range]
[rule.range-val-in-closure]
[rule.receiver-naming]
[rule.redefines-builtin-id]
[rule.superfluous-else]
[rule.time-naming]
[rule.unexported-return]
[rule.unhandled-error]
[rule.unreachable-code]
[rule.unused-parameter]
[rule.unused-receiver]
[rule.var-declaration]
[rule.var-naming]
[rule.waitgroup-by-value]

A really bad example, but in our scenario, we have many routines reading from processChan where we send another message to have them stop processing. We reuse the channel, but we want to ensure the channel was empty from previous processing.

package main

import "sync"

const (
	chanSize = 10
	maxNums = 100
	modNum = 5
)

func main() {
	wg := sync.WaitGroup{}
	processChan := make(chan int, chanSize)

	wg.Add(1)
	go func() {
		defer wg.Done()
		for i := 0; i < maxNums; i++ {
			processChan <- i
		}
	}()

	wg.Add(1)
	go func() {
		defer wg.Done()

		for i := 0; i < maxNums; i++ {
			if !isValidNum(i) {
				break
			}
		}
	}()

	for range processChan {
	}
}

func isValidNum(i int) bool {
	return i%modNum == 0
}

3. Revive returns an error

myflie.go:34:24: this block is empty, you can remove it

Expected behavior
No error to occur as this is channel draining.

Logs
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: macOS 10.14.6
• Version of Go: v1.14.1

Additional context
We have two workarounds:

1. We can ignore the few lines across our project where we are iterating over a channel, however, it would be nicer if revive knew that this is channel draining.
2. We can delete and recreate the channel, but since the channel is passed around on startup / Dependency Injection, we cannot just "create a new one and reinitialize all services" easily.