Add file_extensions to Sublime syntax file (#878)

tests/common.rs

@@ -14,3 +14,4 @@ pub(crate) use just::unindent;
 pub(crate) use libc::{EXIT_FAILURE, EXIT_SUCCESS};
 pub(crate) use test_utilities::{assert_stdout, tempdir, tmptree};
 pub(crate) use which::which;
+pub(crate) use yaml_rust::YamlLoader;

tests/lib.rs

@@ -26,4 +26,5 @@ mod search;
 mod shebang;
 mod shell;
 mod string;
+mod sublime_syntax;
 mod working_directory;

tests/sublime_syntax.rs

@@ -0,0 +1,7 @@
+use crate::common::*;
+
+#[test]
+fn parse() {
+  let yaml = fs::read_to_string("extras/just.sublime-syntax").unwrap();
+  YamlLoader::load_from_str(&yaml).unwrap();
+}