Highlight ranges include a build stage's definition but not its references in FROM instructions

[rcjsuen]

Highlight ranges are only returned for the first and fourth line when something should be returned for the second line as well.

FROM alpine AS base
FROM base
FROM busybox
COPY --from=base . .

const lib = require("dockerfile-language-service");
const service = lib.DockerfileLanguageServiceFactory.createLanguageService();
const document = `FROM alpine AS base
FROM base
FROM busybox
COPY --from=base . .`

console.log(JSON.stringify(service.computeHighlightRanges(document, { line: 3, character: 14 })));

[
    {
        "range": {
            "start": {
                "line": 0,
                "character": 15
            },
            "end": {
                "line": 0,
                "character": 19
            }
        },
        "kind": 3
    },
    {
        "range": {
            "start": {
                "line": 3,
                "character": 12
            },
            "end": {
                "line": 3,
                "character": 16
            }
        },
        "kind": 2
    }
]