Sync the resistor-color-trio exercise's docs with the latest data. (#…

…661)

exercises/practice/resistor-color-trio/.docs/instructions.md

@@ -12,16 +12,16 @@ For this exercise, you need to know only three things about them:
   The program will take 3 colors as input, and outputs the correct value, in ohms.
   The color bands are encoded as follows:
 
-- Black: 0
-- Brown: 1
-- Red: 2
-- Orange: 3
-- Yellow: 4
-- Green: 5
-- Blue: 6
-- Violet: 7
-- Grey: 8
-- White: 9
+- black: 0
+- brown: 1
+- red: 2
+- orange: 3
+- yellow: 4
+- green: 5
+- blue: 6
+- violet: 7
+- grey: 8
+- white: 9
 
 In Resistor Color Duo you decoded the first two colors.
 For instance: orange-orange got the main value `33`.