fix two typos in db_test
@@ -1604,9 +1604,9 @@ func TestCorrectNumTombstones(t *testing.T) {
// TestBlockRanges checks the following use cases:
// - No samples can be added with timestamps lower than the last block maxt.
-// - The compactor doesn't create overlaping blocks
+// - The compactor doesn't create overlapping blocks
// even when the last blocks is not within the default boundaries.
-// - Lower bondary is based on the smallest sample in the head and
+// - Lower boundary is based on the smallest sample in the head and
// upper boundary is rounded to the configured block range.
//
// This ensures that a snapshot that includes the head and creates a block with a custom time range
