Support direct use of modified named character notation

[hyp3rflow]

fixes #220

• tag: es2023

- version: d048f32e861c2ed4a26f59a50d392918f26da3ba (es2023)
- grammar:
  - productions: 359
    - lexical: 147
    - numeric string: 17
    - syntactic: 195
  - extended productions for web: 28
- algorithms: 2654 (88.96%)
  - complete: 2361
  - incomplete: 293
- algorithm steps: 19535 (96.80%)
  - complete: 18909
  - incomplete: 626
- types: 6999 (93.28%)
  - known: 6529
  - yet: 470
  - unknown: 620
- tables: 89
- type model: 58

• branch: GH-2930

- version: 30dd718ed81baeedbc971a1e5d25ea32bc562f65
- grammar:
  - productions: 374
    - lexical: 162
    - numeric string: 17
    - syntactic: 195
  - extended productions for web: 29
- algorithms: 2774 (88.18%)
  - complete: 2446
  - incomplete: 328
- algorithm steps: 20511 (96.87%)
  - complete: 19870
  - incomplete: 641
- types: 7334 (91.79%)
  - known: 6732
  - yet: 602
  - unknown: 625
- tables: 90
- type model: 58

[jhnaldo]

I slightly changed your implementation. If you have no opinion on this, I will merge this PR. Thanks!

[hyp3rflow]

@jhnaldo LGTM! thanks :) 🚀