We were depending on pkg/stringid to truncate IDs for presentation. While
traditionally, we used a fixed length for "truncated" IDs, this is not
a strict requirement (any ID-prefix should work, but conflicts may
happen on shorter IDs).
This patch adds a local `TruncateID()` utility in the formatter package;
it's currently using the same implementation and length as the
`stringid.TruncateID` function, but may diverge in future.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
e0f4bc699c