Fix typos and formatting in documentation and comments

[sefinek]

[Follow-up to #2637, #2636, #2635]

This PR fixes typos, grammar, and formatting in documentation, comments, and helper text. It also fixes Markdown fragments that were rendered incorrectly in the documentation at https://docs.meshcore.io.

In several places, it also standardizes spelling where British and American English variants were mixed.

Most of the issues were in docs/faq.md. Example fixes:

• https://github.com/meshcore-dev/MeshCore/wiki/Repeater-&-Room-Server-CLI-Reference → https://docs.meshcore.io/cli_commands
• github → GitHub
• Seed XIAO → Seeed XIAO
• Plain URLs were not rendered as clickable links in many places.

The remaining changes are similar in nature: typo, spelling, and formatting fixes...

The PR also normalizes line endings in two JSON files. This does not change their values or configuration.

The introduced changes do not modify the firmware logic or behavior. They only affect documentation, comments, text, and formatting.

Tests

1. Ran git diff --check.
2. Checked documentation rendering on GitHub Pages: https://sefinek.github.io/MeshCore
3. Checked the PR preview before changing its status from Draft to Ready for review.

Screenshots

Before (production)	After (development)