Improve description of equal numbers node

[mmisol]

Purpose

The summary is changed to reflect the fact that it works with numbers
only. Also the port names are declared on the node class to make them
appear in the library.

Looks like this now:

Declarations

Check these if you believe they are true

• The codebase is in a better state after this PR
• Is documented according to the standards
• The level of testing this PR includes is appropriate
• User facing strings, if any, are extracted into *.resx files
• All tests pass using the self-service CI.
• Snapshot of UI changes, if any.
• Changes to the API follow Semantic Versioning and are documented in the API Changes document.
• This PR modifies some build requirements and the readme is updated

Reviewers

@QilongTang @zeusongit

FYIs

@Amoursol

[Amoursol]

LGTM @mmisol !

[QilongTang]

Nice!