You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: reference_definition.go
    path of file: ./repos/mattermost/server/public/shared/markdown
    
    the code of the file until where you have to start completion: // Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.

package markdown

type ReferenceDefinition struct {
	RawDestination Range

	markdown string
	rawLabel stri
    
func parseReferenceDefinition(markdown string, ranges []Range) (*ReferenceDefinition, []Range) {
	raw := ""
	for _, r := range ranges {
		raw += markdown[r.Position:r.End]
	}

	label, next, ok := parseLinkLabel(raw, 0)
	if !ok {
		return nil, nil
	}
	position := next

	if position >= len(raw) || raw[position] != ':' {
		return nil, nil
	}
	position++

	destination, next, ok := parseLinkDestination(raw, nextNonWhitespace(raw, position))
	if !ok {
		return nil, nil
	}
	position = next

	absoluteDestination := relativeToAbsolutePosition(ranges, destination.Position)
	ret := &ReferenceDefinition{
		RawDestination: Range{absoluteDestination, absoluteDestination + destination.End - destination.Position},
		markdown:       markdown,
		rawLabel:       raw[label.Position:label.End],
	}

	if position < len(raw) && isWhitespaceByte(raw[position]) {
		title, next, ok := parseLinkTitle(raw, nextNonWhitespace(raw, position))
		if !ok {
			if nextLine, skippedNonWhitespace := nextLine(raw, position); !skippedNonWhitespace {
				return ret, trimBytesFromRanges(ranges, nextLine)
			}
			return nil, nil
		}
		if nextLine, skippedNonWhitespace := nextLine(raw, next); !skippedNonWhitespace {
			ret.rawTitle = raw[title.Position:title.End]
			return ret, trimBytesFromRanges(ranges, nextLine)
		}
	}

	if nextLine, skippedNonWhitespace := nextLine(raw, position); !skippedNonWhitespace {
		return ret, trimBytesFromRanges(ranges, nextLine)
	}

	return nil, nil
}