Cross page section link using labels don't expand to the section title

[NathanReb]

When cross referencing a section from a different page without a specified text for the link, the label will not be expanded into the corresponding section's title.
For example, if you define the following section in a.mld:

{1:some_label Some Grand Title}

And then later reference it from b.mld as follows:

See {!page-a.some_label}

The paragraph will read "See some_label".

[NathanReb]

This behaviour was originally described in the documentation added in #775. @Julow confirmed it was a bug and not intentional so I created this issue instead.

[dbuenzli]

Should be fixed by #1116