Docs: reintroduce misspelling in valid-typeof example (#9753)

This example is intended to be an invalid `typeof` string, to illustrate that the rule reports an error if the user makes a typo like this. However, the spelling was inadvertently corrected in aedae9d, so the documentation is now incorrect (it says that `valid-typeof` reports an error for that code, when in fact it does not).

docs/rules/valid-typeof.md

@@ -20,7 +20,7 @@ Examples of **incorrect** code for this rule:
 typeof foo === "strnig"
 typeof foo == "undefimed"
 typeof bar != "nunber"
-typeof bar !== "function"
+typeof bar !== "fucntion"
 ```
 
 Examples of **correct** code for this rule: