fix aggregate functions to not fail with special episode names

[zkamvar]

In short, there was a problem if someone named an episode starting with images-, the build would fail (see #511). In addition, even if it did succeed, the link in the page would fail because it would have the images- slug trimmed off.

I have done the following actions to fix this:

1. added tests in tests/testthat/test-utils-aggregate.R
2. removed slug trimming in the make_[thing]_section family of functions
3. added a prefix = TRUE catch in the main aggregate function

I also styled these files using styler

Testing

To test this PR, you can install it locally with remotes::install_github() or pak::pkg_install() and then run the example below.

pak::pkg_install("carpentries/sandpaper#512")

Example

This PR will fix that issue and a working reprex is demonstrated below:

tmp <- tempfile()
sandpaper::create_lesson(tmp, rmd = FALSE, open = FALSE)
#> → Creating Lesson in '/tmp/Rtmp2CZhpv/file17fbe74349550'...
#> ℹ No schedule set, using Rmd files in 'episodes/' directory.
#> → Creating Lesson in '/tmp/Rtmp2CZhpv/file17fbe74349550'...→ To remove this message, define your schedule in 'config.yaml' or use `set_episodes()` to generate it.
#> → Creating Lesson in '/tmp/Rtmp2CZhpv/file17fbe74349550'...────────────────────────────────────────────────────────────────────────────────
#> → Creating Lesson in '/tmp/Rtmp2CZhpv/file17fbe74349550'...ℹ To save this configuration, use
#> 
#> set_episodes(path = path, order = ep, write = TRUE)
#> → Creating Lesson in '/tmp/Rtmp2CZhpv/file17fbe74349550'...✔ First episode created in '/tmp/Rtmp2CZhpv/file17fbe74349550/episodes/introduction.md'
#> → Creating Lesson in '/tmp/Rtmp2CZhpv/file17fbe74349550'...ℹ Workflows up-to-date!
#> → Creating Lesson in '/tmp/Rtmp2CZhpv/file17fbe74349550'...✔ Lesson successfully created in '/tmp/Rtmp2CZhpv/file17fbe74349550'
#> → Creating Lesson in '/tmp/Rtmp2CZhpv/file17fbe74349550'...
#> /tmp/Rtmp2CZhpv/file17fbe74349550
sandpaper::create_episode_md("images and pixels", path = tmp, add = TRUE)
sandpaper::build_lesson(tmp, quiet = TRUE, preview = FALSE)
fs::dir_tree(tmp, recurse = 2)
#> /tmp/Rtmp2CZhpv/file17fbe74349550
#> ├── CODE_OF_CONDUCT.md
#> ├── CONTRIBUTING.md
#> ├── LICENSE.md
#> ├── README.md
#> ├── config.yaml
#> ├── episodes
#> │   ├── data
#> │   ├── fig
#> │   ├── files
#> │   ├── images-and-pixels.md
#> │   └── introduction.md
#> ├── index.md
#> ├── instructors
#> │   └── instructor-notes.md
#> ├── learners
#> │   ├── reference.md
#> │   └── setup.md
#> ├── links.md
#> ├── profiles
#> │   └── learner-profiles.md
#> └── site
#>     ├── DESCRIPTION
#>     ├── README.md
#>     ├── _pkgdown.yaml
#>     ├── built
#>     │   ├── CODE_OF_CONDUCT.md
#>     │   ├── LICENSE.md
#>     │   ├── config.yaml
#>     │   ├── data
#>     │   ├── fig
#>     │   ├── files
#>     │   ├── images-and-pixels.md
#>     │   ├── index.md
#>     │   ├── instructor-notes.md
#>     │   ├── introduction.md
#>     │   ├── learner-profiles.md
#>     │   ├── links.md
#>     │   ├── md5sum.txt
#>     │   ├── reference.md
#>     │   └── setup.md
#>     └── docs
#>         ├── 404.html
#>         ├── CODE_OF_CONDUCT.html
#>         ├── LICENSE.html
#>         ├── aio.html
#>         ├── android-chrome-192x192.png
#>         ├── android-chrome-512x512.png
#>         ├── apple-touch-icon.png
#>         ├── assets
#>         ├── bootstrap-toc.css
#>         ├── bootstrap-toc.js
#>         ├── config.yaml
#>         ├── data
#>         ├── docsearch.css
#>         ├── docsearch.js
#>         ├── favicon-16x16.png
#>         ├── favicon-32x32.png
#>         ├── favicons
#>         ├── fig
#>         ├── files
#>         ├── images-and-pixels.html
#>         ├── images.html
#>         ├── index.html
#>         ├── instructor
#>         ├── instructor-notes.html
#>         ├── introduction.html
#>         ├── key-points.html
#>         ├── link.svg
#>         ├── md5sum.txt
#>         ├── mstile-150x150.png
#>         ├── pkgdown.css
#>         ├── pkgdown.js
#>         ├── pkgdown.yml
#>         ├── profiles.html
#>         ├── reference.html
#>         ├── safari-pinned-tab.svg
#>         ├── site.webmanifest
#>         └── sitemap.xml

^{Created on 2023-09-13 with reprex v2.0.2}
This will fix #511

[zkamvar]

I am going to self-merge this because I would like to make sure the changes are incorporated into #513