Handle cases when bound changed from the default

Author: topecongiro

src/missed_spans.rs

@@ -88,11 +88,9 @@ impl<'a> FmtVisitor<'a> {
 
     fn push_vertical_spaces(&mut self, mut newline_count: usize) {
         // The buffer already has a trailing newline.
-        if self.buffer.cur_offset() == 0 {
-            newline_count = newline_count.checked_sub(1).unwrap_or(0);
-        }
-        let newline_upper_bound = self.config.blank_lines_upper_bound() + 1;
-        let newline_lower_bound = self.config.blank_lines_lower_bound() + 1;
+        let offset = if self.buffer.cur_offset() == 0 { 0 } else { 1 };
+        let newline_upper_bound = self.config.blank_lines_upper_bound() + offset;
+        let newline_lower_bound = self.config.blank_lines_lower_bound() + offset;
         if newline_count > newline_upper_bound {
             newline_count = newline_upper_bound;
         } else if newline_count < newline_lower_bound {