\d is for decimal (#3991)
\d is for decimal (#3991)

* \d is for decimal

As we correctly note [further down the page](https://docs.raku.org/language/regexes#Predefined_character_classes), `\d` matches _decimal digits_ 
(Unicode `Nd`) not all numbers (Unicode `N`).  This commit fixes the description here, adds an example of where that makes a difference, and provides
a way to match against Numbers if that's what the user meant.

* Minor fixes from reviews
MasterDuke17/doc,tbrowder/doc,tbrowder/doc,MasterDuke17/doc,MasterDuke17/doc,tbrowder/doc,tbrowder/doc,MasterDuke17/doc