Correct annotation calculation with annot substr

The commit e1a76bb was ultimately
reverted due to it seeming to introduce an abort signal in CI. It turns
out there's an underlying issue with a compiler flag being broken,
however I've also noticed that the annotation calculation for SubStrings
was incorrect, as it didn't take into account the substring offset or
width. We might as well fix this.

base/strings/annotated.jl

@@ -370,13 +370,16 @@ See also: `annotate!`.
 """
 annotations(s::AnnotatedString) = s.annotations
 
-annotations(s::SubString{<:AnnotatedString}) =
-    annotations(s, s.offset+1:s.offset+s.ncodeunits)
+function annotations(s::SubString{<:AnnotatedString})
+    map(((region, annot),) -> (first(region)-s.offset:last(region)-s.offset, annot),
+        annotations(s.string, s.offset+1:s.offset+s.ncodeunits))
+end
 
 function annotations(s::AnnotatedString, pos::UnitRange{<:Integer})
     # TODO optimise
-    filter(label -> !isempty(intersect(pos, first(label))),
-           s.annotations)
+    Tuple{UnitRange{Int64}, Pair{Symbol, Any}}[
+        (max(first(pos), first(region)):min(last(pos), last(region)), annot)
+        for (region, annot) in s.annotations if !isempty(intersect(pos, region))]
 end
 
 annotations(s::AnnotatedString, pos::Integer) = annotations(s, pos:pos)