pcre2: add a few re-exports

This adds the top-level is_jit_available and version free functions from
the underlying pcre2 crate, and also forwards the max_jit_stack_size
option.

grep-pcre2/src/lib.rs

@@ -10,6 +10,7 @@ extern crate pcre2;
 
 pub use error::{Error, ErrorKind};
 pub use matcher::{RegexCaptures, RegexMatcher, RegexMatcherBuilder};
+pub use pcre2::{is_jit_available, version};
 
 mod error;
 mod matcher;