This is a regression from PR #4615. The underscore for the last 2 chars in "NUMERO D’IMMATRICULATION" is too bold.

URL: http://www.ameli.fr/fileadmin/user_upload/formulaires/S3706.pdf
1.1.215: https://i.imgur.com/up8Y33j.png
0.8.990: https://i.imgur.com/UioZcLB.png

fc1e2483b433134a538cce0acd0ccc76e335cf5f is the first bad commit
commit fc1e2483b433134a538cce0acd0ccc76e335cf5f
Author: Jonas Jenwald
Date:   Fri Apr 11 20:19:39 2014 +0200

```
Enforce minimum line widths
```

composeFn = composeSMaskLuminosity;
    } else {
      composeFn = composeSMaskAlpha;
    }
    
    const PIXELS_TO_PROCESS = 1048576;
    const chunkSize = Math.min(height, Math.ceil(PIXELS_TO_PROCESS / width));
    for (let row = 0; row < height; row += chunkSize) {
      const chunkHeight = Math.min(chunkSize, height - row);
      const maskData = maskCtx.getImageData(0, row, width, chunkHeight);
      const layerData = layerCtx.getImageData(0, row, width, chunkHeight);
      if (hasBackdrop) {
        composeSMaskBackdrop(maskData.data, r0, g0, b0);
      }
      composeFn(maskData.data, layerData.data, transferMap);
      maskCtx.putImageData(layerData, 0, row);
    }
  }
  function composeSMask(ctx, smask, layerCtx, webGLContext) {
    const mask = smask.canvas;
    const maskCtx = smask.context;
    ctx.setTransform(
      smask.scaleX,
      0,
      0,
      smask.scaleY,
      smask.offsetX,
      smask.offsetY
    );
    const backdrop = smask.backdrop || null;