chore: update manpage

Author: Texarkanine

cmatrix.1

@@ -63,7 +63,8 @@ Screen update delay 0 - 9, default 4
 Use this color for matrix (default green).
 Valid colors are green, red, blue, white, yellow, cyan, magenta and black.
 Multiple colors can be specified by separating them with commas (e.g., "red,blue,green").
-When multiple colors are specified, they are used with equal probability.
+When multiple colors are specified, they are used proportionally.
+Repeats are allowed for different mixes (e.g. "red,blue,blue" or "red,red,blue")
 .TP
 .I "\-M message"
 Add a message in the center of cmatrix