TSIndexSignature(node) {
      const leftBracketToken = tokenStore.getFirstToken(node)
      const rightBracketToken = /**@type {Token} */ (
        tokenStore.getTokenAfter(
          node.parameters[node.parameters.length - 1] || leftBracketToken,
          isClosingBracketToken
        )
      )
      processNodeList(node.parameters, leftBracketToken, rightBracketToken, 1)
      const keyLast = rightBracketToken
      if (node.typeAnnotation) {
        const typeAnnotationToken = tokenStore.getFirstToken(
          node.typeAnnotation
        )
        setOffset(
          [
            ...tokenStore.getTokensBetween(keyLast, typeAnnotationToken),
            typeAnnotationToken
          ],
          1,
          leftBracketToken
        )
      }
    }
Process index signature

e.g.
```
const foo: { [bar: string]: string }
//           ^^^^^^^^^^^^^^^^^^^^^
```