Add Norwegian translation.

[jonovik]

Added Norwegian translation.

---
title: "Norsk oversettelse"
output:
  learnr::tutorial:
    language: "no"
runtime: shiny_prerendered
---

```{r exercise, exercise=TRUE}
"ÆØÅ"
```

Running devtools::check() gives the same four test failures as main.

PR task list:

• Update NEWS
• [] Did not add tests (not done for other translations either)
• [] No need to update documentation (devtools::document() did not make any changes)

Details

For my translation to take effect, it appears I had to manually run data-raw/i18n_translations.R to regenerate inst/internals/i18n_translations.rds and inst/internals/i18n_random_phrases.rds.
I added a comment about this to the top of data-raw/i18n_translations.yml.

Updated vignettes/multilang.Rmd:

• Note that language code "no" needs to be quoted because it is a reserved word in YAML.
• Fixed two small bugs:
  • The list of available languages meant to append "(default)" to English, but did not store the result.
  • "zh" was not followed by "Chinese" because the test lng %in% names(languages) fails to match the "zh" in the YAML files in data-raw with the "zh_CN" and "zh_TW" names() defined in the vignette.

Fixed missing capitalization in "(All exercise progress will be reset") in data-raw/i18n_translations.yml.

Fixed typo in "Perseverance" in data-raw/i18n_random_phrases.yml.

[CLAassistant]

All committers have signed the CLA.

[gadenbuie]

Thank you for the translation and for the additional copy edits!