Update lines_with_ticks_demo.py

Add explanatory comments to the example on lines with ticked patheffect

Author: Ruth Nainggolan

examples/lines_bars_and_markers/lines_with_ticks_demo.py

@@ -15,10 +15,12 @@
 import matplotlib.pyplot as plt
 from matplotlib import patheffects
 
+# Plot a straight diagonal line with ticked style path
 fig, ax = plt.subplots(figsize=(6, 6))
 ax.plot([0, 1], [0, 1], label="Line",
         path_effects=[patheffects.withTickedStroke(spacing=7, angle=135)])
 
+# Plot a curved line with ticked style path
 nx = 101
 x = np.linspace(0.0, 1.0, nx)
 y = 0.3*np.sin(x*8) + 0.4