title: How do I override this ESLint TypeScript rule?
body: <p>I want to override the rule <code>@typescript/type-annotation-spacing</code> which determines how many spaces to put before and after <code>:</code> in type annotations.</p>
  
  <p>I would like to override it to have a space before and after <code>:</code>, but the default it to just have one after.</p>
  
  <p>The documentation describes several options for this rule, but it does not give any example of the full syntax for overriding this in the <code>eslintrc.*</code> file.</p>
  
  <p><a href="https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/type-annotation-spacing.md" rel="nofollow noreferrer">https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/type-annotation-spacing.md</a></p>
  
  <pre><code>This rule has an object option:
  
  "before": false, (default for colon) disallows spaces before the colon/arrow.
  "before": true, (default for arrow) requires a space before the colon/arrow.
  "after": true, (default) requires a space after the colon/arrow.
  "after": false, disallows spaces after the colon/arrow.
  "overrides", overrides the default options for type annotations with colon (e.g. const foo: string) and function types with arrow (e.g. type Foo = () =&gt; {}).
  </code></pre>
  
  <p>I tried adding this to my <code>eslintrc</code> file</p>
  
  <pre><code>"rules": {
          "@typescript-eslint/type-annotation-spacing": {
              before: true,
              after: true,
              severity: "warn"
          }
      }
  </code></pre>
  
  <p>but then I get this error:</p>
  
  <pre><code>   Configuration for rule "@typescript-eslint/type-annotation-spacing" is invalid:
          Severity should be one of the following: 0 = off, 1 = warn, 2 = error (you passed '{ before: true, after: true, severity: "warn" }').
  </code></pre>
  
  <p>I tried several other variations, but they all result in a similar error.</p>
  
  <p>What is the correct syntax for this?</p>