* Add Kotlin icon details
The source links to a URL containing the official logo and logo
guidelins for the Kotlin logo. Unfortunately it doesn't specify anything
about the color of the logo. So I picked the color of the icons on the
Kotlin language landing page (https://kotlinlang.org/).
* Add Kotlin logo
Added a Kotlin logo, however Kotlin offers three possible logos we could
use (see the guidelines linked in the icon source). In the order they're
(as of this commit) found in the guidelines, here are SVGs varients:
1)
<svg aria-labelledby="simpleicons-kotlin-icon" role="img" viewBox="0 0
24 24" xmlns="http://www.w3.org/2000/svg"><title
id="simpleicons-kotlin-icon">Kotlin icon</title><path d="M24
0H0v24h24L12.04 11.96 24 0zM12.36 1.18h8.81L.91 21.66V13L12.36
1.18z"/></svg>
2) (found in this commit)
<svg aria-labelledby="simpleicons-kotlin-icon" role="img" viewBox="0 0
24 24" xmlns="http://www.w3.org/2000/svg"><title
id="simpleicons-kotlin-icon">Kotlin icon</title><path d="M1.3
24l11.3-11.5L24 24zM0 0h12L0 12.5zM13.4 0L0 14v10l12-12L24 0z"/></svg>
3)
<svg aria-labelledby="simpleicons-kotlin-icon" role="img" viewBox="0 0
24 24" xmlns="http://www.w3.org/2000/svg"><title
id="simpleicons-kotlin-icon">Kotlin icon</title><path d="M12 12L24
0H0v24h24L12 12z"/></svg>
* Update Kotlin color
Based on the colors in the logo gradient as pointed out by @birjolaxew
