Merge remote-tracking branch 'origin/dygraph' into dygraph

doc/doc_en/PP-OCRv3_introduction_en.md

+English | [简体中文](../doc_ch/PP-OCRv3_introduction.md)

doc/doc_en/add_new_algorithm_en.md

@@ -237,7 +237,7 @@ class MyMetric(object):
 
     def get_metric(self):
         """
-        return metircs {
+        return metrics {
                  'acc': 0,
                  'norm_edit_dis': 0,
             }