Improve error message when language is not detected

[BTWS2]

Describe the bug

could not detect language based on extension.
Please specify the language with the --language flag.Error: Could not detect language based on extension.
    at LanguagePicker.detectLanguage (file:///usr/local/lib/node_modules/@dodona/dolos/node_modules/@dodona/dolos-lib/dist/lib/language.js:113:19)
    at Dolos.analyze (file:///usr/local/lib/node_modules/@dodona/dolos/node_modules/@dodona/dolos-lib/dist/lib/dolos.js:117:53)
    at Dolos.analyzePaths (file:///usr/local/lib/node_modules/@dodona/dolos/node_modules/@dodona/dolos-lib/dist/lib/dolos.js:108:21)
    at async file:///usr/local/lib/node_modules/@dodona/dolos/dist/cli/commands/run.js:77:24
    at async tryCatch (file:///usr/local/lib/node_modules/@dodona/dolos/dist/cli/util/utils.js:102:9)
    at async run (file:///usr/local/lib/node_modules/@dodona/dolos/dist/cli/commands/run.js:62:5)

To Reproduce
Steps to reproduce the behavior:

1. Go to https://dodona.be/en/evaluations/???/
2. Click on 'Detect plagiarism' of a HTML-exercise
3. Oops! Something went wrong: non-zero exit code

Expected behavior
Message that HTML is not supported.

Screenshots

Desktop (please complete the following information):

• OS: Windows 11
• Browser: Chrome

Additional context

• What files were you analyzing? Dodona submissions
• Which language? HTML
• How many? 28

[rien]

Dolos currently does not support HTML exercises (see #1029 (comment) for a reason why), so there is no parser registered for the HTML file extension. I'll create an issue with Dodona so they online include the integration for supported programming languages.

Dolos should give a better error message as well.

[rien]

The same error is shown when a ZIP-file is submitted with no submissions. This error message should be different.