Apply suggestions from code review

Author: dhalbert

adafruit_display_shapes/sparkline.py

@@ -11,7 +11,7 @@
 # add_value` are plotted.
 #
 # The `sparkline` class creates an element suitable for adding to the display using
-# `display.root_group=mySparkline`
+# `display.root_group = mySparkline`
 # or adding to a `displayio.Group` to be displayed.
 #
 # When creating the sparkline, identify the number of `max_items` that will be

examples/display_shapes_sparkline_simpletest.py

@@ -11,7 +11,7 @@
 # `add_value` are plotted.
 #
 # The `sparkline` class creates an element suitable for adding to the display using
-# `display.root_group=mySparkline`
+# `display.root_group = mySparkline`
 # or adding to a `displayio.Group` to be displayed.
 #
 # When creating the sparkline, identify the number of `max_items` that will be

examples/display_shapes_sparkline_ticks.py

@@ -11,7 +11,7 @@
 # using `add_value` are plotted.
 #
 # The `sparkline` class creates an element suitable for adding to the display
-# using `display.root_group=mySparkline` or adding to a `displayio.Group` to be displayed.
+# using `display.root_group = mySparkline` or adding to a `displayio.Group` to be displayed.
 #
 # When creating the sparkline, identify the number of `max_items` that will be
 # included in the graph.

examples/display_shapes_sparkline_triple.py

@@ -11,7 +11,7 @@
 # using `add_value` are plotted.
 #
 # The `sparkline` class creates an element suitable for adding to the display
-# using `display.root_group=mySparkline` or adding to a `displayio.Group` to be displayed.
+# using `display.root_group = mySparkline` or adding to a `displayio.Group` to be displayed.
 #
 # When creating the sparkline, identify the number of `max_items` that will be
 # included in the graph.