chore: 📝 Links in deflist in Rocqnavi comments

[yoshihiro503]

Motivation for this change

probability_theory/random_variable.v

Checklist

• added corresponding entries in CHANGELOG_UNRELEASED.md

• added corresponding documentation in the headers

Reference: How to document

Merge policy

As a rule of thumb:

• PRs with several commits that make sense individually and that
  all compile are preferentially merged into master.
• PRs with disorganized commits are very likely to be squash-rebased.

Reminder to reviewers

• Read this Checklist
• Put a milestone if possible
• Check labels

[affeldt-aist]

@hoheinzollern @proux01 RFC: What do you think about this "feature"? This is low-tech but arguably more stable than adding custom parsing, not very user-friendly but anyway we do not expect use to write tons of documentation.

[proux01]

sounds good