gears.colors() docs: fix pattern string used in the example

In general, patterns are specified as 'type:arguments', where 'arguments' is
specific to the pattern used.  The example provided in the documentation,
defined the pattern type to be 'linear', but used arguments meant to create
radial pattern.  So we modify the example to use the correct type -- 'radial'.

Signed-off-by: Anurag Priyam <anurag08priyam@gmail.com>
Signed-off-by: Uli Schlachter <psychon@znc.in>

lib/gears/color.lua.in

@@ -130,7 +130,7 @@ types = {
 -- This function can create solid, linear, radial and png patterns. In general,
 -- patterns are specified as "type:arguments". "arguments" is specific to the
 -- pattern used. For example, one can use
--- "linear:50,50,10:55,55,30:0,#ff0000:0.5,#00ff00:1,#0000ff"
+-- "radial:50,50,10:55,55,30:0,#ff0000:0.5,#00ff00:1,#0000ff"
 -- Any argument that cannot be understood is passed to create_solid_pattern().
 -- @see create_solid_pattern, create_png_pattern, create_linear_pattern,
 --      create_radial_pattern