Add PhaseFieldX to Sphinx projects list

[CastillonMiguel]

Subject: Add PhaseFieldX to Sphinx projects list

Purpose

• Add the new project “PhaseFieldX” to the list of available projects in Sphinx documentation.

[jayaddison]

Hi @CastillonMiguel - thank you for your pull request. Could I ask what the purpose of adding your documentation to the Sphinx listed projects is?

Please note: there's a syntax problem in your index.rst file - possibly some use of Markdown instead of RST in the contributions/feedback paragraph: https://github.com/CastillonMiguel/phasefieldx/blob/14d39f275acdccbec42d0c937d7cdcfb519d54e0/docs/source/index.rst?plain=1#L34

[CastillonMiguel]

Hi @jayaddison. Thanks for reviewing my pull request and pointing out the syntax issue in the index.rst file—I’ve corrected it.

I added the documentation to the Sphinx listed projects to increase visibility for the open-source PhaseFieldX project and to provide a structured example that others might find useful for their projects.