Update polar.py

examples/projections/nongeo/polar.py

@@ -12,7 +12,7 @@
 
 Limits are set via the ``region`` parameter
 ([*theta_min*, *theta_max*, *radius_min*, *radius_max*]). When using **P**\ *width* you
-have to give the *width* of the figure. The lower-case version **p** is similar to **P**
+have to give the *width* of the figure. The lowercase version **p** is similar to **P**
 but expects a *scale* instead of a width (**p**\ *scale*).
 
 The following customizing modifiers are available: