fix(regression): remove overly strict invalid tag format check in Swig parser

[D-Sketon]

What does it do?

The previous condition ((char !== '%' && next_char === '}') || (char === '%' && next_char !== '}')) (#5618) was too restrictive and incorrectly identified valid tags containing '%' characters (like {% include 11% 22 %}) as invalid format.

This change removes the problematic validation and relies on proper tag ending detection (%}) and the existing backtracking mechanism for handling truly malformed tags.

Screenshots

Pull request tasks

• Add test cases for the changes.
• Passed the CI test.

[github-actions]

How to test

git clone -b fix/8.0.0-1 https://github.com/D-Sketon/hexo.git
cd hexo
npm install
npm test

[coveralls]

Pull Request Test Coverage Report for Build 18785924685

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 99.526%

---

Totals
Change from base Build 18785809217:	0.0%
Covered Lines:	9871
Relevant Lines:	9918

---

💛 - Coveralls