chore: fix typo in testing.md (vuejs#1563)

Author: timorohrer

src/guide/scaling-up/testing.md

@@ -217,7 +217,7 @@ cy.get(valueSelector).should('be.visible').and('contain.text', '0')
 
 - [Cypress Component Testing](https://on.cypress.io/component) for components whose expected behavior depends on properly rendering styles or triggering native DOM events. Can be used with Testing Library via [@testing-library/cypress](https://testing-library.com/docs/cypress-testing-library/intro).
 
-The main differences between Vitest and browser-based runners are speed and execution context. In short, browser-based runners, like Cypress, can catch issues that node-based runners, like Vitest, cannot (e.g. style issues, real native DOM events, cookies, local storage, and network failures), but browser-based runners are *orders of magnitude slower than Vitest* because they doopen a browser, compile your stylesheets, and more. Cypress is a browser-based runner that supports component testing. Please read [Vitest's comparison page](https://vitest.dev/guide/comparisons.html#cypress) for the latest information comparing Vitest and Cypress.
+The main differences between Vitest and browser-based runners are speed and execution context. In short, browser-based runners, like Cypress, can catch issues that node-based runners, like Vitest, cannot (e.g. style issues, real native DOM events, cookies, local storage, and network failures), but browser-based runners are *orders of magnitude slower than Vitest* because they do open a browser, compile your stylesheets, and more. Cypress is a browser-based runner that supports component testing. Please read [Vitest's comparison page](https://vitest.dev/guide/comparisons.html#cypress) for the latest information comparing Vitest and Cypress.
 
 ### Mounting Libraries