fix(doc-printer): use string-width

[ikatyang]

Based on sindresorhus/string-width#15 (comment), stripAnsi should not matter.

EDIT: This PR also fixes these three cases: https://github.com/sindresorhus/string-width/blob/v2.1.1/index.js#L17-L30

[lydell]

Is this refactoring only, or does it fix something?

• Refactoring only: LGTM!
• Fix: We should add a test!

[ikatyang]

Prettier 1.7.4
Playground link

Input:

const x = ["ÁÀĀÉÈĒẸE̩Ẹ́É̩Ẹ̀È̩Ẹ̄Ē̩ÍÌĪÓÒŌỌO̩Ọ́Ó̩Ọ̀Ò̩Ọ̄Ō̩ÚÙŪṢS̩áàāéèēẹe̩ẹ́é̩ẹ̀è̩ẹ̄ē̩íìīóòōọo̩ọ́ó̩ọ̀ò̩ọ̄ō̩úùū"];
//345678901234567890123456789012345678901234567890123456789012345678901234567890
//       1         2         3         4         5         6         7         8

Output:

const x = [
  "ÁÀĀÉÈĒẸE̩Ẹ́É̩Ẹ̀È̩Ẹ̄Ē̩ÍÌĪÓÒŌỌO̩Ọ́Ó̩Ọ̀Ò̩Ọ̄Ō̩ÚÙŪṢS̩áàāéèēẹe̩ẹ́é̩ẹ̀è̩ẹ̄ē̩íìīóòōọo̩ọ́ó̩ọ̀ò̩ọ̄ō̩úùū"
];
//345678901234567890123456789012345678901234567890123456789012345678901234567890
//       1         2         3         4         5         6         7         8

Expected:

const x = ["ÁÀĀÉÈĒẸE̩Ẹ́É̩Ẹ̀È̩Ẹ̄Ē̩ÍÌĪÓÒŌỌO̩Ọ́Ó̩Ọ̀Ò̩Ọ̄Ō̩ÚÙŪṢS̩áàāéèēẹe̩ẹ́é̩ẹ̀è̩ẹ̄ē̩íìīóòōọo̩ọ́ó̩ọ̀ò̩ọ̄ō̩úùū"];
//345678901234567890123456789012345678901234567890123456789012345678901234567890
//       1         2         3         4         5         6         7         8

[lydell]

Nice 👌