[html2] change html2 mustache to fix parameter name

[johnluan]

PR checklist

• Read the contribution guildelines.
• Ran the shell/batch script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates)
• Filed the PR against the correct branch: master for non-breaking changes and 2.3.0 branch for breaking (non-backward compatible) changes.

Description of the PR

Considering html2 as generating document instead of code, so there should be baseName in the page.
Otherwise, the parameter will be changed if the parameter doesn't follow the element rules.
e.g. parameter name as aa_bb_cc, then the document will change it as aaBbCc, which is confused for the document users. So highly recommend to change it to baseName.

[wing328]

Thanks for the PR but your commit (as shown in the Commits tab) is not linked to your Github account, which means this PR won't count as your contribution in https://github.com/swagger-api/swagger-codegen/graphs/contributors.

Let me know if you need help fixing it.

Ref: https://github.com/swagger-api/swagger-codegen/wiki/FAQ#how-can-i-update-commits-that-are-not-linked-to-my-github-account