Add countAnsiEscapeCodes option

[fisker]

Same as sindresorhus/string-length#16, add an option to count ANSI escape codes.
Previously requested by #15, and Prettier do need count them.

[fisker]

#47 should fix the CI.

[sindresorhus]

Can you fix the conflict?

[sindresorhus]

CI is failing:

 index.test-d.ts:5:36
  ✖  5:36  Argument of type { ambiguousIsNarrow: false; } is not assignable to parameter of type Options.
  Property countAnsiEscapeCodes is missing in type { ambiguousIsNarrow: false; } but required in type Options.   
  ✖  6:55  Argument of type { countAnsiEscapeCodes: true; } is not assignable to parameter of type Options.
  Property ambiguousIsNarrow is missing in type { countAnsiEscapeCodes: true; } but required in type Options.  

  2 errors

[fisker]

Fixed.