Fix instructions typo

README.rst

@@ -45,7 +45,7 @@ Example Usage
 Single video feed:
 ::
 
-    python sksurgerydavinci -v 0 -m MODEL_DIR
+    python sksurgerydavinci -s 0 -m MODEL_DIR
 
 -m specifies the location of a directory containing vtl/stl/vtp/ply models.
 
@@ -53,18 +53,18 @@ Stereo video feed:
 
 ::
 
-    python sksurgerydavinci -v 0 1 -m MODEL_DIR
+    python sksurgerydavinci -s 0 1 -m MODEL_DIR
 
 Mock stereo feed using only one input:
 ::
 
-    python sksurgerydavinci -v 0 -1 -m MODEL_DIR
+    python sksurgerydavinci -s 0 -1 -m MODEL_DIR
 
 If 3 or more screens are available, each video feed will run full screen on a separate display.
 Video feeds can be assigned to specific displays using the -o arugment:
 ::
 
-    python sksurgerydavinci -v 0 1 -o 2 3 1
+    python sksurgerydavinci -s 0 1 -o 2 3 1
 
 More details on command line arguments can be viewed using:
 ::