add doc comment for get_syntax_test_assertions

Author: keith-hall

src/syntax_tests.rs

@@ -33,6 +33,10 @@ pub struct SyntaxTestAssertionRange {
     scope_selector_text: String,
 }
 
+/// Given a start token, option end token and text, parse the syntax tests in the text
+/// that follow the format described at http://www.sublimetext.com/docs/3/syntax.html#testing
+/// and return the scope selector assertions found, so that when the text is parsed,
+/// the assertions can be checked
 pub fn get_syntax_test_assertions(token_start: &str, token_end: Option<&str>, text: &str) -> Vec<SyntaxTestAssertionRange> {
     let mut assertions = Vec::new();
     let mut test_line_offset = 0;