Update CHANGELOG.md

Author: steveukx

simple-git/CHANGELOG.md

@@ -4,7 +4,7 @@
 
 ### Minor Changes
 
-- f2fc5c9: Show full commit hash in a `CommitResult`, prior to this change `git.commit` resulted in a partial hash in the `commit` property, following this change the `commit` property contains a full hash.
+- f2fc5c9: Show full commit hash in a `CommitResult`, prior to this change `git.commit` would result in a partial hash in the `commit` property if `core.abbrev` is unset or has a value under `40`. Following this change the `commit` property will contain the full commit hash.
 
 ### Patch Changes