repository: improve commondir docs Fixes #5428
diff --git a/include/git2/repository.h b/include/git2/repository.h
index 45d7962..9ddcd34 100644
--- a/include/git2/repository.h
+++ b/include/git2/repository.h
@@ -481,10 +481,11 @@ GIT_EXTERN(const char *) git_repository_path(const git_repository *repo);
GIT_EXTERN(const char *) git_repository_workdir(const git_repository *repo);
/**
- * Get the path of the shared common directory for this repository
- *
- * If the repository is bare is not a worktree, the git directory
- * path is returned.
+ * Get the path of the shared common directory for this repository.
+ *
+ * If the repository is bare, it is the root directory for the repository.
+ * If the repository is a worktree, it is the parent repo's gitdir.
+ * Otherwise, it is the gitdir.
*
* @param repo A repository object
* @return the path to the common dir