Fix doc failure on nightly.

Fix #41.

Cargo.toml

@@ -2,7 +2,7 @@
 name = "qrcode"
 description = "QR code encoder in Rust"
 license = "MIT OR Apache-2.0"
-version = "0.11.1"
+version = "0.11.2"
 edition = "2018"
 authors = ["kennytm <kennytm@gmail.com>"]
 keywords = ["qrcode"]

src/ec.rs

@@ -13,9 +13,9 @@ use crate::types::{EcLevel, QrResult, Version};
 /// 69 bytes. Longer blocks will result in task panic.
 ///
 /// This method treats the data as a polynomial of the form
-/// (a[0] x<sup>m+n</sup> + a[1] x<sup>m+n-1</sup> + … + a[m] x<sup>n</sup>) in
-/// GF(256), and then computes the polynomial modulus with a generator
-/// polynomial of degree N.
+/// (a\[0\] x<sup>m+n</sup> + a\[1\] x<sup>m+n-1</sup> + … + a\[m\] x<sup>n</sup>)
+/// in GF(2<sup>8</sup>), and then computes the polynomial modulus with a
+/// generator polynomial of degree N.
 pub fn create_error_correction_code(data: &[u8], ec_code_size: usize) -> Vec<u8> {
     let data_len = data.len();
     let log_den = GENERATOR_POLYNOMIALS[ec_code_size];