fix(escapeAllSwigTags): backtrack when tag is incomplete

[D-Sketon]

What does it do?

fix #5571
fix #5301
fix hexojs/hexo-renderer-pandoc#60

Screenshots

Pull request tasks

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

[github-actions]

How to test

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

[coveralls]

Pull Request Test Coverage Report for Build 13286910631

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 144 of 145 (99.31%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.01%) to 99.462%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
lib/hexo/post.ts	144	145	99.31%

Totals
Change from base Build 13176180491:	0.01%
Covered Lines:	9791
Relevant Lines:	9844

---

💛 - Coveralls

[D-Sketon]

In fact, this is a tricky problem—when the incomplete first part of the tag and the incomplete second part of the tag are concatenated, they form a complete tag, which is then parsed as Swig.

For the following text 123 {#} 123 {#} 123, I think Hexo could parse it as either 123 {#} 123 {#} 123 or 123 <!-- swig 0 --> 123.