doc: fix typos

PR #1605

crates/regex/src/matcher.rs

@@ -253,7 +253,7 @@ impl RegexMatcherBuilder {
     /// they should impose a limit on the length, in bytes, of the concrete
     /// pattern string. In particular, this is viable since this parser
     /// implementation will limit itself to heap space proportional to the
-    /// lenth of the pattern string.
+    /// length of the pattern string.
     ///
     /// Note that a nest limit of `0` will return a nest limit error for most
     /// patterns but not all. For example, a nest limit of `0` permits `a` but