Provides access to element labels
Processing an element in the
label.markup mode produces the
element label.
Trailing punctuation is not added to the label.
.
Request for label of unexpected element:
label.markup: this can't happen!
Returns true if $section should be labelled
Returns true if the specified section should be labelled.
By default, this template simply returns $section.autolabel, but
custom stylesheets may override it to get more selective behavior.