Summary

Fix navigation menu handling of external URLs and update documentation to clarify external URL support.

Related issue

Fixes #480

Changes

This PR fixes a bug where external URLs in the navigation menu were being treated as relative URLs, resulting in incorrect paths like http://127.0.0.1:1111/https://example.com/. The fix:

1. Adds URL type detection to check if URLs start with "http"
2. Handles external URLs directly without using get_url()
3. Updates documentation to clarify external URL support and usage

This implements the same fix that was previously applied to the footer menu (#212).

Type of change

• Bug fix (fixes an issue without altering functionality)
• New feature (adds non-breaking functionality)
• Breaking change (alters existing functionality)
• UI/UX improvement (enhances user interface without altering functionality)
• Refactor (improves code quality without altering functionality)
• Documentation update
• Other (please describe below)

Checklist

• I have verified the accessibility of my changes
• I have tested all possible scenarios for this change
• I have updated theme.toml with a sane default for the feature
• I have updated config.toml in tabi-start
• I have made corresponding changes to the documentation:
• Updated config.toml comments
• Updated theme.toml comments
• Updated "Mastering tabi" post in English
• (Optional) Updated "Mastering tabi" post in Spanish
• (Optional) Updated "Mastering tabi" post in Catalan