[gnome-builder] Rename some Rust snippets to more suitable names

[Christian Hergert <chergert src gnome org>]

commit 7781d0d7c5905ef27d38e7e38c8ad6478c75a519
Author: Ricardo Silva Veloso <ricvelozo gmail com>
Date:   Thu Aug 23 23:13:22 2018 -0300

    Rename some Rust snippets to more suitable names

 data/snippets/rust.snippets | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/data/snippets/rust.snippets b/data/snippets/rust.snippets
index 66d9f483b..6c9fabfb4 100644
--- a/data/snippets/rust.snippets
+++ b/data/snippets/rust.snippets
@@ -85,8 +85,8 @@ snippet impl
        impl ${1:Type} {
            $0
        }
-snippet impltrait
-- desc Implement trait
+snippet implfor
+- desc impl … for
        impl ${1:Trait} for ${2:Type} {
            $0
        }
@@ -104,7 +104,7 @@ snippet drop
                $0
            }
        }
-snippet constructor
+snippet new
 - desc Create a constructor
        #[inline]
        pub fn ${1:new}(${2}) -> Self {