linter: Improve config generation for website to support string-based configs

[connorshea]

There is no way currently to generate the config docs correctly for a rule like prefer_es6_class. In this case, there isn't a config object, but rather just a string value for the mode to run the rule in:

"react/prefer-es6-class": ["error", "always"]

Right now the auto-generated config doesn't really handle this pattern correctly and we need to update the website generation logic to allow this.

Other rules with this behavior that need this change:

• vue/define-emits-declaration
• vue/define-props-declaration (although this is technically defined as taking a bool, which is somewhat wrong?)
• eslint/operator-assignment
• jest/no_restricted_matchers.rs this one isn't string-based, but does have the same problem.
• eslint/yoda accepts a string argument of always
• eslint/func-names - this supports one string config option and then a keyword argument as well.
• unicorn/switch-case-braces