giterr_set: consistent error messages

Error messages should be sentence fragments, and therefore:

1. Should not begin with a capital letter,
2. Should not conclude with punctuation, and
3. Should not end a sentence and begin a new one

1 files changed, 2 insertions, 2 deletions

diff --git a/src/patch_generate.c b/src/patch_generate.c
index 0e5d1db31..3559cc2b8 100644
--- a/src/patch_generate.c
+++ b/src/patch_generate.c
@@ -417,7 +417,7 @@ static int diff_required(git_diff *diff, const char *action)
 {
 	if (diff)
 		return 0;
-	giterr_set(GITERR_INVALID, "Must provide valid diff to %s", action);
+	giterr_set(GITERR_INVALID, "must provide valid diff to %s", action);
 	return -1;
 }
 
@@ -776,7 +776,7 @@ int git_patch_generated_from_diff(
 
 	delta = git_vector_get(&diff->deltas, idx);
 	if (!delta) {
-		giterr_set(GITERR_INVALID, "Index out of range for delta in diff");
+		giterr_set(GITERR_INVALID, "index out of range for delta in diff");
 		return GIT_ENOTFOUND;
 	}