More links on authority pages etc

[confirmordeny]

Relevant issue(s)

This would add more links to some of the authority pages if the relevant tags are present.

(1) Research Organization Registry (ROR) - https://ror.org/ - based on "ror:" tag. (2) London Stock Exchange - https://www.londonstockexchange.com/ - based on "lon:" tag.

Also, there is a minor wording correction to a help page.

What does this do?

See above.

Why was this needed?

See above.

Implementation notes

N/A.

Screenshots

N/A.

Notes to reviewer

See above.

[gbp]

Merged in 3a540da

[confirmordeny]

Thank you.