Add docs comments and tests for TypeScript definitions (#299)

Fixes #293

readme.md

@@ -178,15 +178,15 @@ Explicit 256/Truecolor mode can be enabled using the `--color=256` and `--color=
 
 ### Modifiers
 
-- `reset`
-- `bold`
-- `dim`
-- `italic` *(Not widely supported)*
-- `underline`
-- `inverse`
-- `hidden`
-- `strikethrough` *(Not widely supported)*
-- `visible` (Text is emitted only if enabled)
+- `reset` - Resets the current color chain.
+- `bold` - Make text bold.
+- `dim` - Emitting only a small amount of light.
+- `italic` - Make text italic. *(Not widely supported)*
+- `underline` - Make text underline. *(Not widely supported)*
+- `inverse`- Inverse background and foreground colors.
+- `hidden` - Prints the text, but makes it invisible.
+- `strikethrough` - Puts a horizontal line through the center of the text. *(Not widely supported)*
+- `visible`- Prints the text only when Chalk is enabled. Can be useful for things that are purely cosmetic.
 
 ### Colors