update docs

Author: louisnw01

docs/source/reference/abstract_chart.md

@@ -181,14 +181,6 @@ ___
 
 
 
-```{py:method} remove_horizontal_line(price: NUM)
-
-Removes a horizontal line at the given price.
-```
-___
-
-
-
 ```{py:method} clear_markers()
 
 Clears the markers displayed on the data.
@@ -197,14 +189,6 @@ ___
 
 
 
-```{py:method} clear_horizontal_lines()
-
-Clears the horizontal lines displayed on the data.
-```
-___
-
-
-
 ```{py:method} precision(precision: int)
 
 Sets the precision of the chart based on the given number of decimal places.