doc: fix Cypher documentation link in README

[bitflicker64]

Purpose of the PR

• Fix incorrect link to Cypher wiki; point to Cypher query language documentation instead.

Main Changes

• Updated the Cypher reference link to point to the official Cypher query language documentation.

Verifying these changes

• Trivial rework / code cleanup without any test coverage. (No Need)
• Already covered by existing tests, such as (please modify tests here).
• Need tests and can be verified as follows:
  • xxx

Does this PR potentially affect the following parts?

• Dependencies (add/update license info & regenerate_known_dependencies.sh)
• Modify configurations
• The public API
• Other affects (typed here)
• Nope

Documentation Status

• Doc - TODO
• Doc - Done
• Doc - No Need

[imbajin]

THX

[bitflicker64]

Thanks for the review!