Improve Notebook documentation to include Dataprovider

fix #5975

docs/strategy_analysis_example.md

@@ -50,7 +50,9 @@ candles.head()
 ```python
 # Load strategy using values set above
 from freqtrade.resolvers import StrategyResolver
+from freqtrade.data.dataprovider import DataProvider
 strategy = StrategyResolver.load_strategy(config)
+strategy.dp = DataProvider(config, None, None)
 
 # Generate buy/sell signals using strategy
 df = strategy.analyze_ticker(candles, {'pair': pair})
@@ -228,7 +230,7 @@ graph = generate_candlestick_graph(pair=pair,
 # Show graph inline
 # graph.show()
 
-# Render graph in a separate window
+# Render graph in a seperate window
 graph.show(renderer="browser")
 
 ```

freqtrade/templates/strategy_analysis_example.ipynb

@@ -79,7 +79,9 @@
    "source": [
     "# Load strategy using values set above\n",
     "from freqtrade.resolvers import StrategyResolver\n",
+    "from freqtrade.data.dataprovider import DataProvider\n",
     "strategy = StrategyResolver.load_strategy(config)\n",
+    "strategy.dp = DataProvider(config, None, None)\n",
     "\n",
     "# Generate buy/sell signals using strategy\n",
     "df = strategy.analyze_ticker(candles, {'pair': pair})\n",