Fix alignment doc in usage.md

docs/usage.md

@@ -23,7 +23,7 @@ wer = jiwer.wer(reference, hypothesis)
 mer = jiwer.mer(reference, hypothesis)
 wil = jiwer.wil(reference, hypothesis)
 
-# faster, because `compute_measures` only needs to perform the heavy lifting once:
+# faster, because `process_words` only needs to perform the heavy lifting once:
 output = jiwer.process_words(reference, hypothesis)
 wer = output.wer
 mer = output.mer
@@ -58,10 +58,9 @@ error = output.cer
 
 # Alignment
 
-With `jiwer.process_words`, you also get the alignment between the reference and hypothesis.
+With `jiwer.process_words` and `jiwer.process_characters`, you get the alignment between the reference and hypothesis.
 
-We provide the alignment as a list of `(op, ref_start_idx, ref_idx_end, hyp_idx_start, hyp_idx_end)`, where `op` is one of
-    `equal`, `replace`, `delete`, or `insert`.
+We provide the alignment as a list of `AlignmentChunk` objects with attributes `type, ref_start_idx, ref_end_idx, hyp_start_idx, hyp_end_idx`, where `type` is one of `equal`, `substitute`, `delete`, or `insert`.
 
 This looks like the following: