Fix typos in pivot point comments (mementum#383)

Author: discosultan

backtrader/indicators/pivotpoint.py

@@ -135,11 +135,11 @@ class FibonacciPivotPoint(Indicator):
     Formula:
       - pivot = (h + l + c) / 3  # variants duplicate close or add open
       - support1 = p - level1 * (high - low)  # level1 0.382
-      - support2 = p - level2 * (high - low)  # level1 0.618
-      - support2 = p - level3 * (high - low)  # level1 1.000
+      - support2 = p - level2 * (high - low)  # level2 0.618
+      - support3 = p - level3 * (high - low)  # level3 1.000
       - resistance1 = p + level1 * (high - low)  # level1 0.382
-      - resistance2 = p + level2 * (high - low)  # level1 0.618
-      - resistance2 = p + level3 * (high - low)  # level1 1.000
+      - resistance2 = p + level2 * (high - low)  # level2 0.618
+      - resistance3 = p + level3 * (high - low)  # level3 1.000
 
     See:
       - http://stockcharts.com/school/doku.php?id=chart_school:technical_indicators:pivot_points