Improve method docs of Pico::load404Content()
Improve method docs of Pico::load404Content()

picocms/Pico,lukasz-jakub-adamczuk/tech-jump-guide,fabianacero/fabianacerog,ondrejd/Pico,lukasz-jakub-adamczuk/tech-jump-guide,lukasz-jakub-adamczuk/tech-jump-guide,PhrozenByte/Pico,TakamiChie/Pico,fabianacero/fabianacerog,TakamiChie/Pico,ondrejd/Pico,theshka/Pico,TakamiChie/Pico,dav-m85/Pico,dav-m85/Pico,theshka/Pico,theshka/Pico,smcdougall/Pico,picocms/Pico,dav-m85/Pico,smcdougall/Pico,TakamiChie/Pico,PhrozenByte/Pico,picocms/Pico,smcdougall/Pico,ondrejd/Pico,fabianacero/fabianacerog,PhrozenByte/Pico