Fix broken anchor links in docs

[Steve-Mcl]

Description

Addresses snapshots link issue

• #compare-snapshots
  • updated the links to recently renamed section title
• #Instance-owned-devices
  • capital letter in section link

Addresses docker/kubernetes broken link

• #enable-https-optional
  • I am not sure where this originally linked to but I have pointed the link in docs/install/kubernetes/README.md to the existing section in the docker.md - not 100% sure if that was the intention - please check.
• #after-starting-the-platform-i-cant-access-it-in-the-browser---i-see-connection-refused-error
  • This link was working in editor. suspect the punctuation of length of the section title is not playing nicely with the link checker. I simplified the title of this one.

Regarding the docker broken link,

Related Issue(s)

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
• Documentation has been updated
  • Upgrade instructions
  • Configuration details
  • Concepts
• Changes flowforge.yml?
  • Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production

Labels

• Includes a DB migration? -> add the area:migration label