capitalize method
Capitalizes a String.
Implementation
String? capitalize({String separator = ' ', String replaceWith = ' '}) {
if (this == null) return null;
String capitalized = '';
List<String> splits = this!.split(separator);
for (int i = 0; i < splits.length; i++) {
String s = splits[i];
capitalized += '${s[0].toUpperCase()}${s.substring(1)}';
if (i < splits.length - 1) capitalized += replaceWith;
}
return capitalized;
}