Fix ascii art

Documentation/pycardium/display.rst

@@ -4,14 +4,16 @@
 The display module let's you draw on the card10's display.
 Pixels are addressed from top left to bottom right with a range of x: 0 to 159 and y: 0 to 79.
 
-0,0
-   +---------------------+
-   |                     |
-   |                     |
-   |                     |
-   |                     |
-   +---------------------+
-                          159,79
+.. code-block:: text
+
+   0,0
+      +---------------------+
+      |                     |
+      |                     |
+      |                     |
+      |                     |
+      +---------------------+
+                           159,79
 
 Drawing operations are clipped, pixels outside of the screen will be ignored.