docs: add missing word in threads section (#1093)

docs/guide/features.md

@@ -33,7 +33,7 @@ ESM first, top level await
 
 ## Threads
 
-Workers multi-threading via [tinypool](https://github.com/Aslemammad/tinypool) (a lightweight fork of [Piscina](https://github.com/piscinajs/piscina)), allowing tests to run simultaneously. Threads are enabled by default Vitest, and can be disabled passing `--no-threads` in the CLI.
+Workers multi-threading via [tinypool](https://github.com/Aslemammad/tinypool) (a lightweight fork of [Piscina](https://github.com/piscinajs/piscina)), allowing tests to run simultaneously. Threads are enabled by default in Vitest, and can be disabled passing `--no-threads` in the CLI.
 
 Vitest also isolates each file's environment so env mutations in one file don't affect others. Isolation can be disabled by passing `--no-isolate` to the CLI (trading of correctness for run performance).