(chore) Update SUPPORTED_LANGUAGES.md to add `arduino` (#2639)
(chore) Update SUPPORTED_LANGUAGES.md to add `arduino` (#2639)


carlokok/highlight.js,isagalaev/highlight.js,highlightjs/highlight.js,highlightjs/highlight.js,highlightjs/highlight.js,isagalaev/highlight.js,carlokok/highlight.js,carlokok/highlight.js,highlightjs/highlight.js,carlokok/highlight.js