Minor speedup

This continue should be a break. The current form doesn't cause errors
but using a break will be a bit faster.

spacy/ml/models/coref_util.py

@@ -128,9 +128,10 @@ def get_candidate_mentions(
         si = sentence_map[tok.i]  # sentence index
         for ii in range(1, max_span_width):
             ei = tok.i + ii  # end index
+
             # Note: this matches slice syntax, so the token index is one less
             if ei > len(doc) or sentence_map[ei - 1] != si:
-                continue
+                break
 
             begins.append(tok.i)
             ends.append(ei)