Start with windows drive letter is also valid if its length is 2.

Author: o0Ignition0o

src/parser.rs

@@ -1539,8 +1539,20 @@ fn starts_with_windows_drive_letter(s: &str) -> bool {
     ascii_alpha(s.as_bytes()[0] as char) && matches!(s.as_bytes()[1], b':' | b'|')
 }
 
+/// https://url.spec.whatwg.org/#start-with-a-windows-drive-letter
 fn starts_with_windows_drive_letter_segment(input: &Input) -> bool {
     let mut input = input.clone();
-    matches!((input.next(), input.next(), input.next()), (Some(a), Some(b), Some(c))
-             if ascii_alpha(a) && matches!(b, ':' | '|') && matches!(c, '/' | '\\' | '?' | '#'))
+    match (input.next(), input.next(), input.next()) {
+        // its first two code points are a Windows drive letter
+        // its third code point is U+002F (/), U+005C (\), U+003F (?), or U+0023 (#).
+        (Some(a), Some(b), Some(c))
+            if ascii_alpha(a) && matches!(b, ':' | '|') && matches!(c, '/' | '\\' | '?' | '#') =>
+        {
+            true
+        }
+        // its first two code points are a Windows drive letter
+        // its length is 2
+        (Some(a), Some(b), None) if ascii_alpha(a) && matches!(b, ':' | '|') => true,
+        _ => false,
+    }
 }