pastel: add page (#3443)

pages/common/pastel.md

@@ -0,0 +1,24 @@
+# pastel
+
+> Generate, analyze, convert and manipulate colors.
+> More information: <https://github.com/sharkdp/pastel>.
+
+- Convert colors from one format to another. Here from RGB to HSL:
+
+`pastel format {{hsl}} {{ff8000}}`
+
+- Show and analyze colors on the terminal:
+
+`pastel color "{{rgb(255,50,127)}}"`
+
+- Pick a color from somewhere on the screen:
+
+`pastel pick`
+
+- Generate a set of N visually distinct colors:
+
+`pastel distinct {{8}}`
+
+- Get a list of all X11 / CSS color names:
+
+`pastel list`