abbreviate method
Abbreviate a string to maxWidth by truncating the
string and adding '...' to then truncated string.
If offset is passed then the we begin abbreviating
from that index into the string.
'Hello World'.abbreviate(6) == 'Hel...'
The minimum value for maxWidth is 4
Implementation
String abbreviate(int maxWidth, {int offset = 0}) =>
Part.abbreviate(this, maxWidth);