Rename ast to parser

Signed-off-by: Marcel Müller <neikos@neikos.email>

tests/file_tests.rs

@@ -45,7 +45,7 @@ fn check_for_input([path]: [&Path; 1]) {
 
     insta::assert_debug_snapshot!(format!("{basename}.1-parsed"), parsed);
 
-    let ast = match nomo::ast::parse(parsed.tokens()) {
+    let ast = match nomo::parser::parse(parsed.tokens()) {
         Ok(ast) => ast,
         Err(err) => {
             eprintln!("{}", err.to_report(input));