Fix handle of space at start or last

[codecov-commenter]

Codecov Report

Merging #376 (7a9ece1) into master (42fb764) will not change coverage. The diff coverage is 100.00%.

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #376 +/- ## ======================================= Coverage 75.61% 75.61% ======================================= Files 13 13 Lines 4650 4650 ======================================= Hits 3516 3516 Misses 874 874 Partials 260 260 ```

[ozraru]

@goccy Could you review, please?

[goccy]

@ozraru Basically, the spaces before and after are automatically removed and converted to tokens, so please add specific use cases to the test cases (e.g. encode_test.go and decode_test.go )

[ozraru]

@goccy done

[goccy]

LGTM