Show how to reference a line within a repository file.

See the general Documentation guidelines http://docs.gitlab.com/ce/development/doc_styleguide.html

What does this MR do?

Extends the list of example repository references by showing how to reference a line within a file.

Moving docs to a new location?

No.

• If working on CE, submit an MR to EE with the changes as well.

@marcelhuberfoo Thank you for contributing this documentation change!

added ~164274 ~15078 labels

changed milestone to %9.0

assigned to @rymai

@marcelhuberfoo Thanks, looks good to me! No need to create a merge request against EE here. ;)

merged

mentioned in commit 9ce16b48