findNextMatch abstract method
Returns the leftmost match at or after start in line, breaking ties
by pattern order. Returns null if no pattern matches.
allowA says whether \A may match (only on a document's first
line). allowG says whether \G may match at start. Both follow
vscode-textmate.
Implementation
ScanMatch? findNextMatch(
String line,
int start, {
required bool allowA,
required bool allowG,
});