Ground work for composable documents, fix for running HTML2PDF on Windows, some CSS styles for RST

What's Changed

• Bump version to 0.0.49 by @stanislaw in #1700
• html2pdf: fix the issue of running within virtual environments by @stanislaw in #1702
• Migration from Fragments to includable Documents by @stanislaw in #1703
• backend/sdoc: remove last occurrences of Fragment, document the change by @stanislaw in #1704
• export/html: show the "included documents" only when there are included docs by @stanislaw in #1705
• UI: Diff screen: do not build source file traceability when doing history by @stanislaw in #1708
• docs: FAQ: resources: FOSDEM 2024 by @stanislaw in #1710
• export/html: project_index: Show fragments by default, disable switcher, add info about including file by @mettta in #1711
• Styles: add CSS for RST admonition markup by @mettta in #1712

Full Changelog: 0.0.49...0.0.50

What's Changed

• Bump version to 0.0.49 by @stanislaw in #1700
• html2pdf: fix the issue of running within virtual environments by @stanislaw in #1702
• Migration from Fragments to includable Documents by @stanislaw in #1703
• backend/sdoc: remove last occurrences of Fragment, document the change by @stanislaw in #1704
• export/html: show the "included documents" only when there are included docs by @stanislaw in #1705
• UI: Diff screen: do not build source file traceability when doing history by @stanislaw in #1708
• docs: FAQ: resources: FOSDEM 2024 by @stanislaw in #1710
• export/html: project_index: Show fragments by default, disable switcher, add info about including file by @mettta in #1711
• Styles: add CSS for RST admonition markup by @mettta in #1712
• Bump version to 0.0.50 by @stanislaw in #1713
• docs: regenerate Read the Docs by @stanislaw in #1714

Full Changelog: 0.0.49...0.0.50