[@typescript-eslint/naming-convention] Migration guide for deprecated rules

[rbuckton]

In 3.0.0 a number of rules were deprecated in favor of naming-convention, however the configuration for naming-convention is fairly different from that of the rules it subsumed. Migrating from the old rules to naming-convention is less than straightforward and the documentation for the old rules is not helpful:

It would be extremely useful to provide information in these older docs on how to migrate from usages of these old rules to the naming-convention rule.

[bradzacher]

Have you checked out the docs for naming-convention - the end of the doc contains an examples section which covers a few of the cases such as:

• Enforce that type parameters (generics) are prefixed with T (the generic-type-naming rule)
• Enforce that interface names do not begin with an I (the interface-name-prefix rule)
• Enforce the codebase follows ESLint's camelcase conventions (both the camelcase rule and the class-name-casing rule)
• Enforce that private members are prefixed with an underscore (the member-naming rule)

https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/naming-convention.md#examples

[rbuckton]

I did see these, but it would be helpful to at least link to them from the deprecated docs.

[bradzacher]

camelcase is the only rule doc that I left behind when I deleted the rules in an attempt to "stave off" issues from people clicking into a docs to find a replacement for the base camelcase rule.

Happy to accept a PR to add a link directly to the mentioned example