Improve error message for missin [cli] extra

If you copy paste the current message in bash / zsh it will error out with:

```
» pip install --upgrade hypothesis[cli]
zsh: no matches found: hypothesis[cli]
```

Author: sobolevn

hypothesis-python/src/hypothesis/extra/cli.py

@@ -53,7 +53,7 @@
 The Hypothesis command-line interface requires the `{}` package,
 which you do not have installed.  Run:
 
-    python -m pip install --upgrade hypothesis[cli]
+    python -m pip install --upgrade 'hypothesis[cli]'
 
 and try again.
 """