Rust unstable API change causes compilation error of unstable `pattern` feature

[yhx-12243]

As the title says, the rust standard library add a function to the unstable Pattern trait, so these code will cause a compilation error.

regex/src/pattern.rs

Lines 13 to 24 in bcbe403

	impl<'r> Pattern for &'r Regex {
	type Searcher<'t> = RegexSearcher<'r, 't>;
	fn into_searcher<'t>(self, haystack: &'t str) -> RegexSearcher<'r, 't> {
	RegexSearcher {
	haystack,
	it: self.find_iter(haystack),
	last_step_end: 0,
	next_match: None,
	}
	}
	}

[BurntSushi]

#1232

[BurntSushi]

This fixed in regex 1.11.1 on crates.io.