Update clippy helper function types

Author: GrishaVar

src/tools/clippy/clippy_lints/src/regex.rs

@@ -81,7 +81,7 @@ impl<'tcx> LateLintPass<'tcx> for Regex {
 
 #[allow(clippy::cast_possible_truncation)] // truncation very unlikely here
 #[must_use]
-fn str_span(base: Span, c: regex_syntax::ast::Span, offset: u16) -> Span {
+fn str_span(base: Span, c: regex_syntax::ast::Span, offset: u8) -> Span {
     let offset = u32::from(offset);
     let end = base.lo() + BytePos(u32::try_from(c.end.offset).expect("offset too large") + offset);
     let start = base.lo() + BytePos(u32::try_from(c.start.offset).expect("offset too large") + offset);