Fix doc links

[jordanjohnson56]

Issue

Documentation links on pages other than index.md point to non-existent paths, returning a 404 error when trying to navigate between pages via the on-page links. The sidebar links work fine, as do links on the homepage.

Cause

The links in the documentation markdown are written without file extensions, so mkdocs appends them as sub paths of the current URL, e.g. https://libmodbus.org/reference/modbus_new_tcp/modbus_tcp_listen (does not exist) instead of https://libmodbus.org/reference/modbus_tcp_listen. This doesn't cause an issue on the index page as the current URL is https://libmodbus.org/reference, therefore appending the sub path creates a valid link.

Fix

Adding file extensions to the markdown links causes mkdocs to create valid links.

Changes

• .md was added to the documentation links so mkdocs produces the correct links
• Fixed a typo for one of the links in index.md

[cla-bot]

We require contributors to sign our Contributor License Agreement. In order for us to review and merge your code, please fill https://forms.gle/5635zjphDo5JEJQSA to get added. Your document will be manually checked by the maintainer. Be patient...

[jordanjohnson56]

I believe I filled out the CLA. Let me know if I need to fill it out again.

[stephane]

Good catch. Thank you.