Bold text intersects itself, causing an ugly effect when fading

Relates to MC-108323 and MC-277445.

The bug

Bold text is self-intersecting in a way what causes the translucency fading animation to look incorrect.

How to reproduce

/title @a title {"text":"■", "bold": true, "shadow_color": 0}

Expected results

The rectangle would fade out uniformly.

Actual results

The horizontal center remains twice as opaque as the outer edges when fading out.

How to fix

Instead of rendering text twice, it may make more sense to pre-generate bold characters and stitch them to their own font atlas so they only need to be rendered a single time. In addition to eliminating this issue, it would also reduce rendering lag.