Do not count /*/ as both start and end comment (rust-lang#3185)

Author: Alan Du

src/comment.rs

@@ -312,15 +312,23 @@ fn identify_comment(
             let closer = style.closer().trim_left();
             let mut closing_symbol_offset = 0;
             let mut hbl = false;
+            let mut first = true;
             for line in orig.lines() {
                 closing_symbol_offset += compute_len(&orig[closing_symbol_offset..], line);
-                let trimmed_line = line.trim_left();
+                let mut trimmed_line = line.trim_left();
                 if !trimmed_line.starts_with('*')
                     && !trimmed_line.starts_with("//")
                     && !trimmed_line.starts_with("/*")
                 {
                     hbl = true;
                 }
+
+                // Remove opener from consideration when searching for closer
+                if first {
+                    let opener = style.opener().trim_right();
+                    trimmed_line = &trimmed_line[opener.len()..];
+                    first = false;
+                }
                 if trimmed_line.ends_with(closer) {
                     break;
                 }

tests/target/issue-3184.rs

@@ -0,0 +1,5 @@
+/*/
+struct Error{
+    message: String,
+}
+*/