Categorize rules in docs as one of Possible Problems, Suggestions, and Formatting

[golopot]

These categories help readers find rules more quickly. A user interested in Possible Problems rules can look at Possible Problems rules. A user interested in formatting rules can look at formatting rules.

[ljharb]

Why? All things are possible problems, including formatting rules.

[golopot]

Possible problems catches codes with bugs. I don't care about formatting rules because I use prettier.

[ljharb]

Prettier doesn’t format everything, and anything it handles is disabled by eslint-config-prettier.

[golopot]

Yes but the categorization it is still useful for when I need to find a rule I need. For example, when I need to find a rule thats warns about unmemoized context value, I know it is a possible problem instead of a formatting issue, so in this case I only need to scan about 10 rules instead of 80 rules.

[golopot]

Suppose it is Friday, and the product would be released today, and you can only fix one of possible problems or formatting issue, which one will you choose?

[ljharb]

Since formatting issues are autofixable, I can't conceive of when that would come up in the first place.

If we can automatically generate this information in the readme, I'd be happy to review a PR.