Lint Cleanup

This remove some stores that clang assures me are very dead.

And an assert() for an unlikely NULL pointer dereference I can't quite
figure out.

src/reader.cpp

@@ -2176,6 +2176,7 @@ static int threaded_highlight(background_highlight_context_t *ctx) {
 ///        an asynchronous highlight in the background, which may perform disk I/O.
 static void reader_super_highlight_me_plenty(int match_highlight_pos_adjust, bool no_io) {
     const editable_line_t *el = &data->command_line;
+    assert (el != NULL);
     long match_highlight_pos = (long)el->position + match_highlight_pos_adjust;
     assert(match_highlight_pos >= 0);