Updated hints for events and materials

[PhilReedData]

Summary of changes

• As described in docs issue 8 Write all definitions from materials and events and learning paths docs#8 some of the events and materials hints can be updated and expanded, aligned to the new docs.
• Does not include a few materials hints to return to in the future:
  • Scientific Topics / Keywords (maybe these labels are missing?)
  • Target Audience
  • Competency Levels

Motivation and context

• Follows feedback from the Flemish RDM group testing Spaces.

Checklist

• I have read and followed the CONTRIBUTING guide.
• I confirm that I have the authority necessary to make this contribution on behalf of its copyright owner and agree
  to license it to the TeSS codebase under the
  BSD license.

[PhilReedData]

thanks @fbacall , I have committed edits to your suggestions.