docs: add describe.skipIf documentation (#2558)

* add describe.skipIf documentation

* Update index.md

* Apply suggestions from code review

Co-authored-by: Anjorin Damilare <damilareanjorin1@gmail.com>

Co-authored-by: Robbe <robbe@dexxter.be>
Co-authored-by: Vladimir <sleuths.slews0s@icloud.com>
Co-authored-by: Anjorin Damilare <damilareanjorin1@gmail.com>

docs/api/index.md

@@ -497,6 +497,26 @@ When you use `test` or `bench` in the top level of file, they are collected as p
   })
   ```
 
+### describe.skipIf
+
+- **Type:** `(condition: any) => void`
+
+  In some cases, you might run suites multiple times with different environments, and some of the suites might be environment-specific. Instead of wrapping the suite with `if`, you can use `describe.skipIf` to skip the suite whenever the condition is truthy.
+
+  ```ts
+  import { assert, test } from 'vitest'
+
+  const isDev = process.env.NODE_ENV === 'development'
+
+  describe.skipIf(isDev)('prod only test', () => {
+    // this test only runs in production
+  })
+  ```
+
+::: warning
+You cannot use this syntax when using Vitest as [type checker](/guide/testing-types).
+:::
+
 ### describe.only
 
 - **Type:** `(name: string, fn: TestFunction, options?: number | TestOptions) => void`