Improve community standards

[alinacherkas]

While the package is mature and feature-rich, there is some room for enhancing developer experience in line with the community standards. I am opening this issue to propose a number of changes to the project to strengthen its quality standards.

• add issue and pull request templates - many popular open-source packages, e.g. pandas and dplyr, provide standard issue templates to standardise bug reporting and feature requests.
• add contributing guidelines - similar to the above, clear guidelines for contributors could attract more contributions from community members.
• code formatting - the R community is slowly catching up with Python in terms of code quality tools. The styler package is nowadays a de factor formatter for R code and is widely adopted by the community. Since the version 2024.12.0, RStudio also supports automatic code formatting "on save". With this, collapse could benefit from consistent formatting using styler. In particular, I suggest that
  1. all code in the project is formatter with styler. Since this will affect most project files, it is best to perform formatting when only a few branches/WIPs exist to mitigate potential conflicts.
  2. styler is added to .Rproj as the default code formatter.

[SebKrantz]

Thanks! I agree with points 1 and 2. I won't apply styler to the package because I do some unorthodox things (like nesting .Call's) to make the package fast which are usually written on one line. I like the way the code is written now.

[SebKrantz]

Thanks again. I think this should do.