Calculates the span, defined in Range indexes, that includes start through to end character positions.
start
end
After using splitRanges to split text, lineSpan is used to associate some text coordinates with ranges.
lineSpan
Ranges
Start character position, in source text reference
End character position, in source text reference
Span
Calculates the span, defined in Range indexes, that includes
startthrough toendcharacter positions.After using splitRanges to split text,
lineSpanis used to associate some text coordinates with ranges.