When rendering typos, we look up what visual column the typoe starts on
but I mixed a raw byte offset with the offset into a lossy string. This
caused panics when dealing with non-ascii content.
Fixes#258
I didn't count on how `buffer.lines().count()` would handle different
corner cases, like slices with no `\n`, slices with trailing `\n`, etc.
Fixes#259
At some point early on, this project was renamed from "scorrect" to
"typos". Some references to old URLs still exist. This commit corrects
those references.