BUG: Fix plot not shown in VSCode Jupyter

Fixes #695

Author: kernc

backtesting/_plotting.py

@@ -46,7 +46,8 @@
           encoding='utf-8') as _f:
     _AUTOSCALE_JS_CALLBACK = _f.read()
 
-IS_JUPYTER_NOTEBOOK = 'JPY_PARENT_PID' in os.environ
+IS_JUPYTER_NOTEBOOK = ('JPY_PARENT_PID' in os.environ or
+                       'inline' in os.environ.get('MPLBACKEND', ''))
 
 if IS_JUPYTER_NOTEBOOK:
     warnings.warn('Jupyter Notebook detected. '