Add standardized recommended/fixable/suggestions notices to rule docs

[bmish]

Included changes:

• Adds standardized notices to the top of each rule doc to indicate whether the rule is in the recommended config, autofixable, or has automated suggestions
• Adds a test to verify each rule doc has the correct notices

These notices match the notices used by ESLint itself and many other ESLint plugins:

• https://eslint.org/docs/rules/no-useless-escape
• https://github.com/ember-cli/eslint-plugin-ember/blob/master/docs/rules/no-get.md
• https://github.com/platinumazure/eslint-plugin-qunit/blob/master/docs/rules/no-assert-equal.md
• https://github.com/not-an-aardvark/eslint-plugin-eslint-plugin/blob/master/docs/rules/no-only-tests.md
• https://github.com/ember-template-lint/ember-template-lint/blob/master/docs/rule/no-negated-condition.md

These notices ensure each rule doc clearly provides several critical data points by itself, without the reader having to refer to the readme rules table which has the same information.

[sindresorhus]

How should we handle cases like this? https://github.com/sindresorhus/eslint-plugin-unicorn/pull/1586/files#diff-c6117e5638d17c7f095600f9b360e53d3f652539ca0d37d670d6bc4e50840cbdR5

[bmish]

How should we handle cases like this? #1586 (files)

I think it's fine for rule docs to optionally provide more detailed information about which specific cases are fixable or suggestable. In fact, some rule docs already include this information (This rule is fixable when ...), and I left this information intact (in addition to my new standardized notices which are based purely on the rule meta properties).