Fix outdated docs and use ` instead of <code>
Fix outdated docs and use ` instead of <code>

maxmind/GeoIP2-php,g9007676/GeoIP2-php,cemoulto/GeoIP2-php,maxmind/GeoIP2-php,cemoulto/GeoIP2-php,Shemtek/GeoIP,g9007676/GeoIP2-php