Fix a typo

"Can not" has a different meaning than "cannot".

README.md

@@ -102,7 +102,7 @@ in question.
 
 If you want to run a benchmark *without an intermediate shell*, you can use the `-N` or `--shell=none`
 option. This is helpful for very fast commands (< 5 ms) where the shell startup overhead correction would
-produce a significant amount of noise. Note that you can not use shell syntax like `*` or `~` in this case.
+produce a significant amount of noise. Note that you cannot use shell syntax like `*` or `~` in this case.
 ```
 hyperfine -N 'grep TODO /home/user'
 ```