Fabian Homborg 34fc390e13 [git completions] Shorten commit SHA ourselves
This is much quicker - on the order of 100ms vs 50ms.

We shorten to 10 characters, which is statistically suitable - 3 out
of 600k commits in the linux kernel need 11 characters.
2018-05-08 23:12:13 +02:00
..
2018-05-08 22:52:16 +02:00