fix hang for incomplete raw strings

corpus/literals.txt

@@ -264,6 +264,24 @@ let _ = ##"Hello, so-called "world"!"##
     (raw_string_literal
       (raw_str_end_part))))
 
+================================================================================
+Doesn't hang for incomplete raw strings (issue #146)
+================================================================================
+
+let _ = #"Foo"
+
+---
+
+(source_file
+  (property_declaration
+    (value_binding_pattern
+      (non_binding_pattern
+        (wildcard_pattern)))
+    (ERROR
+      (UNEXPECTED '"'))
+    (line_string_literal
+      (line_str_text))))
+
 ================================================================================
 Raw strings with interpolation
 ================================================================================

src/scanner.c

@@ -512,7 +512,7 @@ static bool eat_raw_str_part(
         uint8_t last_char = '\0';
         lexer->mark_end(lexer); // We always want to parse thru the start of the string so far
         // Advance through anything that isn't a hash symbol, because we want to count those.
-        while (lexer->lookahead != '#') {
+        while (lexer->lookahead != '#' && lexer->lookahead != '\0') {
             last_char = lexer->lookahead;
             advance(lexer);
             if (last_char != '\\') {