message: syntax/doc: fix typo
diff: @@ -26,7 +26,7 @@ This crate defines two primary types:
  syntax and the low level compiled opcodes that are eventually responsible for
  executing a regular expression search. Given some high-level IR, it is not
  possible to produce the original concrete syntax (although it is possible to
  - produce an equivalent conrete syntax, but it will likely scarcely resemble
  + produce an equivalent concrete syntax, but it will likely scarcely resemble
  the original pattern). To a first approximation, the high-level IR is simple
  and easy to analyze.
  