Update gradient.jl

Author: sl-solution

src/gradient.jl

@@ -1,3 +1,14 @@
+"""
+    gradient(colors...; direction = [0,1,0,0])
+
+A linear gradient interpolates colors along a line, from a starting point to an ending point. By default a linear gradient runs horizontally, from left to right. Use the direction to configure the gradient direction, e.g. [0,0,0,1] runs the gradient vertically. All coordinates are defined in a normalized [0, 1] coordinate space, relative to the bounding box of the item being colored.
+
+## Examples
+```julia
+gradient()
+gradient(:red, :white, :blue)
+```
+"""
 function gradient(args...; direction = [0,1,0,0])
     res = Dict{Symbol, Any}()
     res[:gradient] = :linear