Use implicit reference style links

See:
- <https://daringfireball.net/projects/markdown/syntax#link>
- <https://github.github.com/gfm/#collapsed-reference-link>

ROADMAP.md

@@ -23,9 +23,8 @@ Code quality release
 - [ ] Add flake8 + plugins (see
       <https://github.com/psf/black/blob/main/.pre-commit-config.yaml>)
 - [ ] Add mypy or other type checker
-- [ ] Add more pre-commit hooks AKA  
-      Fix [#28](https://github.com/apptension/onetimepass/issues/28)
-- [ ] Fix [#60](https://github.com/apptension/onetimepass/issues/60)
+- [ ] Add more pre-commit hooks AKA Fix [#28][]
+- [ ] Fix [#60][]
 
 Optionally:
 - [ ] Add tool to find unused code (vulture?)
@@ -35,42 +34,53 @@ Optionally:
     - <https://github.com/features/security>
     - <https://snyk.io/>
     - <https://aquasecurity.github.io/trivy/v0.32/>
-- [ ] Add [pyroma](<https://pypi.org/project/pyroma/>)
+- [ ] Add [pyroma][]
+
+[#28]: https://github.com/apptension/onetimepass/issues/28
+[#60]: https://github.com/apptension/onetimepass/issues/60
+[pyroma]: https://pypi.org/project/pyroma/
 
 ## 0.4.0
 
 Unit tests release
 
-See [#30](https://github.com/apptension/onetimepass/issues/30)
+See [#30][]
 
 Part of 0.3.0 instead?
 
 - [ ] Add unit tests (possibly full coverage)
 - [ ] Add coverage checker to the CI/CD
 - [ ] Add per platform testing (Linux, macOS, Windows)
 
+[#30]: https://github.com/apptension/onetimepass/issues/30
+
 ## 0.5.0
 
 Better docs release
 
 May be swapped in order with **Publish package release**
 
-- [ ] Fix [#29](https://github.com/apptension/onetimepass/issues/29)
-- [ ] Fix [#55](https://github.com/apptension/onetimepass/issues/55)
-- [ ] Fix [#59](https://github.com/apptension/onetimepass/issues/59)
-- [ ] Consider the general rewrite.
+- [ ] Fix [#29][]
+- [ ] Fix [#55][]
+- [ ] Fix [#59][]
+- [ ] Consider the general rewrite
+
+[#29]: https://github.com/apptension/onetimepass/issues/29
+[#55]: https://github.com/apptension/onetimepass/issues/55
+[#59]: https://github.com/apptension/onetimepass/issues/59
 
 ## 0.6.0
 
 Publish package release
 
 May be swapped in order with **Better docs release**
 
-- [ ] Publish automatically on tag to PyPI AKA  
-      Fix [#35](https://github.com/apptension/onetimepass/issues/35)
+- [ ] Publish automatically on tag to PyPI AKA Fix [#35][]
 - [ ] Implement PKGBUILD for Arch Linux (see
       <https://wiki.archlinux.org/title/Python_package_guidelines>)
 - [ ] Implement Homebrew formula for macOS
 - [ ] Zipapp or similar for Windows (research required)
-- [ ] Document how to install the app on the mobile phone AKA  
-      Fix [#36](https://github.com/apptension/onetimepass/issues/36)
+- [ ] Document how to install the app on the mobile phone AKA Fix [#36][]
+
+[#35]: https://github.com/apptension/onetimepass/issues/35
+[#36]: https://github.com/apptension/onetimepass/issues/36