regex: migrate grep-regex to regex-automata

We just do a "basic" dumb migration. We don't try to improve anything
here.

crates/globset/src/lib.rs

@@ -498,13 +498,23 @@ impl GlobSetBuilder {
 /// Constructing candidates has a very small cost associated with it, so
 /// callers may find it beneficial to amortize that cost when matching a single
 /// path against multiple globs or sets of globs.
-#[derive(Clone, Debug)]
+#[derive(Clone)]
 pub struct Candidate<'a> {
     path: Cow<'a, [u8]>,
     basename: Cow<'a, [u8]>,
     ext: Cow<'a, [u8]>,
 }
 
+impl<'a> std::fmt::Debug for Candidate<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        f.debug_struct("Candidate")
+            .field("path", &self.path.as_bstr())
+            .field("basename", &self.basename.as_bstr())
+            .field("ext", &self.ext.as_bstr())
+            .finish()
+    }
+}
+
 impl<'a> Candidate<'a> {
     /// Create a new candidate for matching from the given path.
     pub fn new<P: AsRef<Path> + ?Sized>(path: &'a P) -> Candidate<'a> {