enhance: doc gen tool support escape html option

[amyXia1994]

1. Does this PR affect any open issues?(Y/N) and add issue references (e.g. "fix #123", "re #123".):

• N
• Y

related to #139

2. What is the scope of this PR (e.g. component or file name):

cmds/kcl-go/command/cmd_doc.go
pkg/tools/gen/gendoc.go

pkg/tools/gen/gendoc_test.go

pkg/tools/gen/templates/doc/packageDoc.gotmpl
pkg/tools/gen/templates/doc/schemaDoc.gotmpl

pkg/tools/gen/testdata/doc/

3. Provide a description of the PR(e.g. more details, effects, motivations or doc link):

enhance: doc gen tool support escape html option

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Other

4. Are there any breaking changes?(Y/N) and describe the breaking changes(e.g. more details, motivations or doc link):

• N
• Y

5. Are there test cases for these changes?(Y/N) select and add more details, references or doc links:

• Unit test
• Integration test
• Benchmark (add benchmark stats below)
• Manual test (add detailed scripts or steps below)
• Other

[coveralls]

Pull Request Test Coverage Report for Build 6000232301

• 16 of 18 (88.89%) changed or added relevant lines in 1 file are covered.
• 3 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.08%) to 64.139%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/tools/gen/gendoc.go	16	18	88.89%

Files with Coverage Reduction	New Missed Lines	%
pkg/tools/gen/gendoc.go	3	67.5%

Totals
Change from base Build 5975056464:	0.08%
Covered Lines:	2470
Relevant Lines:	3851

---

💛 - Coveralls

[Peefy]

LGTM