docs: fix compile errors for whitespace wrapper recipe (#1764)

doc/nom_recipes.md

@@ -35,15 +35,13 @@ use nom::{
 
 /// A combinator that takes a parser `inner` and produces a parser that also consumes both leading and 
 /// trailing whitespace, returning the output of `inner`.
-fn ws<'a, F, O, E: ParseError<&'a str>>(inner: F) -> impl Parser<&'a str>
-  where
-  F: Parser<&'a str>,
+pub fn ws<'a, O, E: ParseError<&'a str>, F>(
+    inner: F,
+) -> impl FnMut(&'a str) -> IResult<&'a str, O, E>
+where
+    F: Parser<&'a str, O, E>,
 {
-  delimited(
-    multispace0,
-    inner,
-    multispace0
-  )
+    delimited(multispace0, inner, multispace0)
 }
 ```