Servo `Range` type probably predates the `Range` type in the standard
library. The fact that there are two `Range` types in Servo is often
very confusing. The internal type is only used for byte indices in glyph
runs. This change removes the internal generic `Range` in favor of a
small wrapper around a native Rust `Range`.
It's likely that there are more improvements that could be done here,
such as reusing `Utf8CodePointIndex`, but this code is going to change a
lot soon and these ranges might soon be replaced with actual glyph
ranges. We are going to be looking to remove `TextByteRange` entirely.
This is just an intermediate step.
Testing: This should not change behavior and is thus covered by existing
tests.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
30fa32714e