Update python-tracing.md

Ref: [awsdocs#215](aws/aws-xray-sdk-python#215) & https://github.com/awsdocs/aws-xray-developer-guide/blob/master/doc-source/xray-sdk-python-patching.md

Author: aniljaiswal

doc_source/python-tracing.md

@@ -60,8 +60,9 @@ boto3
 requests
 sqlite3
 mysql
+pymysql
 You can use `patch_all()` to patch all of them at once\. 
 
 Following is what a trace emitted by the code preceding looks like \(synchronous invocation\): 
 
-![\[Image NOT FOUND\]](http://docs.aws.amazon.com/lambda/latest/dg/images/AWS_X_Ray_Python.png)
+![\[Image NOT FOUND\]](http://docs.aws.amazon.com/lambda/latest/dg/images/AWS_X_Ray_Python.png)