Fix wrong reading from commit
Fix wrong reading from commit

Right now we use a substr after reading the commit. That's definitely
wrong and leads to wrong commit hashes since the first 5 chars are
missing.

This patch removes the substr usage here and this way fixes the
generated links.

Signed-off-by: Sheogorath <1c2647ce2ee8a4ec8e5c8b1b245ca38f94844bab@shivering-isles.com>

jackycute/HackMD,hackmdio/hackmd,Yukaii/hackmd,hackmdio/hackmd,jackycute/HackMD,Yukaii/hackmd,jackycute/HackMD,Yukaii/hackmd,hackmdio/hackmd