Merge pull request #3280 from sclu1034/issue/3270

Improve gears.shape module description.

lib/gears/shape.lua

@@ -4,8 +4,9 @@
 -- It add the concept of "shape" to Awesome. A shape can be applied to a
 -- background, a margin, a mask or a drawable shape bounding.
 --
--- The functions exposed by this module always take a context as first
--- parameter followed by the widget and height and additional parameters.
+-- The functions exposed by this module always take a cairo context as first
+-- parameter followed by a width and height. Individual functions may take
+-- additional parameters for their specific implementions.
 --
 -- The functions provided by this module only create a path in the content.
 -- to actually draw the content, use `cr:fill()`, `cr:mask()`, `cr:clip()` or