Bug: Uncaught undefined for reporting after a code block

[DMartens]

Issue

Currently there is a guard for messages which report before the code block, but not if the message reports for a line after the code block.
This leads to an error in the block.rangeMap[lineInCode].indent access,
as block.rangeMap[lineInCode] evaluates to undefined.
I am willing to create an PR for this.

Minimal Reproduction

Markdown (I had to create an invalid document as the markdown renderer does not support nested code blocks):

Empty code block:
`` `js
`` `

Rule:

export default {
	create(context) {
		return {
			Program() {
				context.report({ message: 'message', loc: { start: { line: 2, column: 1 } } })
			}
		};
	}
}

[nzakas]

Thanks for reporting this. It's definitely a bug we should get fixed. Please feel free to submit a PR.