Update brush-preset thumbnail: Ink (partial set)

Two presets in 4.x were similar to two of my brushkit:

• Ink Tought ( Fill brush on my side )
• Ink Precision (annotation brush on my side).

I merged ( I kept the settings of 4.x and decorated the presets
with icon of my brushkit ) because the settings in 4.x were
superior ; more precise, better curve and optimised.

Ink Leaky has now a feather artwork and Ink Fineliner has a
tubular pen with a 0.5 and red coating.