Fix typo and add example (untitaker#9)

examples/tokenize.rs

@@ -0,0 +1,9 @@
+//! Let's you easily try out the tokenizer with e.g.
+//! printf '<h1>Hello world!</h1>' | cargo run --example=tokenize
+use html5gum::{BufReadReader, Tokenizer};
+
+fn main() {
+    for token in Tokenizer::new(BufReadReader::new(std::io::stdin().lock())).flatten() {
+        println!("{:?}", token);
+    }
+}

tests/test_html5lib.rs

@@ -5,7 +5,7 @@ use std::{collections::BTreeMap, fs::File, io::BufReader, path::Path};
 
 #[cfg(not(feature = "integration-tests"))]
 compile_error!(
-    "integration tests need the integration-tests feature enabled. Run cargo tests --all-features"
+    "integration tests need the integration-tests feature enabled. Run cargo test --all-features"
 );
 
 struct ExpectedOutputTokens(Vec<Token>);