[librsvg] PathBuilder: Use map().sum() instead of fold()

[Federico Mena Quintero <federico src gnome org>]

commit a31f56e30c1534a4aa1aa6b36004e4dea6146324
Author: Federico Mena Quintero <federico gnome org>
Date:   Fri Mar 27 13:16:02 2020 -0600

    PathBuilder: Use map().sum() instead of fold()
    
    Thanks to Sergey Bugaev for the suggestion.

 rsvg_internals/src/path_builder.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/rsvg_internals/src/path_builder.rs b/rsvg_internals/src/path_builder.rs
index 10839ab0..7544c505 100644
--- a/rsvg_internals/src/path_builder.rs
+++ b/rsvg_internals/src/path_builder.rs
@@ -480,7 +480,8 @@ impl PathBuilder {
         let num_coords = self
             .path_commands
             .iter()
-            .fold(0, |acc, cmd| acc + cmd.num_coordinates());
+            .map(PathCommand::num_coordinates)
+            .sum();
 
         let mut packed_commands = Vec::with_capacity(num_commands);
         let mut coords = vec![0.0; num_coords];