fix: typo in a comment

Author: bahmutov

cypress/support/commands.js

@@ -21,5 +21,5 @@
 // Cypress.Commands.add('dismiss', { prevSubject: 'optional'}, (subject, options) => { ... })
 //
 //
-// -- This is will overwrite an existing command --
+// -- This will overwrite an existing command --
 // Cypress.Commands.overwrite('visit', (originalFn, url, options) => { ... })