src/sage/plot/graphics.py: Use more block tags

Author: Matthias Koeppe

src/sage/plot/graphics.py

@@ -1890,10 +1890,11 @@ def show(self, **kwds):
 
         ::
 
-            sage: y = x^5 + 4*x^4 - 10*x^3 - 40*x^2 + 9*x + 36                          # needs sage.symbolic
-            sage: p = plot(y, -4.1, 1.1)                                                # needs sage.symbolic
-            sage: xlines = lambda a, b: [z for z, m in y.roots()]                       # needs sage.symbolic
-            sage: p.show(gridlines=[xlines, [0]], frame=True, axes=False)               # needs sage.symbolic
+            sage: # needs sage.symbolic
+            sage: y = x^5 + 4*x^4 - 10*x^3 - 40*x^2 + 9*x + 36
+            sage: p = plot(y, -4.1, 1.1)
+            sage: xlines = lambda a, b: [z for z, m in y.roots()]
+            sage: p.show(gridlines=[xlines, [0]], frame=True, axes=False)
 
         Change the style of all the grid lines.
 
@@ -2730,9 +2731,9 @@ def matplotlib(self, filename=None,
         The patch changes them to float before creating `matplotlib` objects.::
 
             sage: # long time, needs sage.symbolic
-            sage: f = lambda x, y: abs(cos((x + I * y) ** 4)) - 1               # long time, needs sage.symbolic
-            sage: g = implicit_plot(f, (-4, 4), (-3, 3), linewidth=0.6)         # long time, needs sage.symbolic
-            sage: gm = g.matplotlib()                                           # long time, needs sage.symbolic
+            sage: f = lambda x, y: abs(cos((x + I * y) ** 4)) - 1
+            sage: g = implicit_plot(f, (-4, 4), (-3, 3), linewidth=0.6)
+            sage: gm = g.matplotlib()
 
         If the axes are flipped, the limits of the axes get swapped::