Update vector elements.

Tweaks the list of might-be-multi-valued header items to match those required by #1394 and #1395.
Here's a question. The docstring for this function says:

> Define the field components used in the structure analysis.

With all these new sections being returned, is this still true? Are these all used in the analysis to define the structure? If not, should these fields be introduced in a different place?