[Skip-changelog] Improve documentation regarding `ARDUINO_BOARD_MANAGER_ADDITIONAL_URLS`#2136

Merged

MatteoPologruto merged 2 commits intoarduino:masterfrom

MatteoPologruto:comma-separated-additional-urls

Apr 12, 2023

Commits on Apr 3, 2023

Print error message if `board_manager.additional_urls` contains comma separated urls
MatteoPologruto
committed
Improve documentation regarding the usage of environment variables
MatteoPologruto
committed