[Shortcircuits] Units of currents are in A and not kA

[colinepiloquet]

Please check if the PR fulfills these requirements

• [x] The commit message follows our guidelines
• [x] Docs have been added / updated (for bug fixes / features)

Does this PR already have an issue describing the problem?

No

What kind of change does this PR introduce?

Docs update, the currents in the short-circuit results are given in A.