Add autocomplete support for the should(chainer, ...) variants

Environment:

cypress-testing-library version: 5.3.0
node version: 12.13.1
npm (or yarn) version: 6.12.1
typescript version: 3.7.4
Intellij Ultimate version: 2019.3.3

Relevant code or config:

  // ts.config
  "compilerOptions": {
    "strict": true,
    "baseUrl": "../node_modules",
    "target": "es5",
    "lib": ["es5", "dom"],
    "types": ["cypress", "@types/testing-library__cypress"],
    "noEmit": false
  },

// support/index.ts
import "@testing-library/cypress/add-commands";

What you did:

cy.findAllByText('"Some text').should('have.length', 2);

What happened:

You get a warning and no autocompletion. The code runs just fine.

Problem description:

When using the cy.get().should()-syntax in Cypress, you get autocompletion for all the "chainer" variants (as in should("chainer")). Using e.g cy.findByText().should() from CTL will not only give you a linter warning, but also no autocompletion.

Suggested solution:

If there is an existing solution to this issue, please add it to the readme. Alternatively: perhaps it would be possible to add the Typescript definitions for each should-variant as they have done for the original cy.get().should()-variants?

testing-library / cypress-testing-library

Add autocomplete support for the should(chainer, ...) variants #131