Fix reference to install section

[rettichschnidi]

For references to work, the use of backticks, not apostrophes is required.

Also, the reference has to actually exist.

Tasks

• Reviewed contribution guidelines
• PR is descriptively titled 📑 and links the original issue above 🔗
• Tests pass -- look for a green checkbox ✔️ a few minutes after opening your PR
  Run tests locally to check for errors.
• Commits are in uniquely-named feature branch and has no merge conflicts 📁
• Looked for possible updates in documentation and added updates if applicable
• Updated CHANGELOG.rst

[pombredanne]

Good catch! Thank you ++

[AyanSinhaMahapatra]

Thanks++ @rettichschnidi
LGTM, merging!