Use abs_diff as suggested by clippy

    error: manual absolute difference pattern without using `abs_diff`
       --> x11rb/src/xcb_ffi/mod.rs:692:9
        |
    692 | /         if value > recent {
    693 | |             value - recent
    694 | |         } else {
    695 | |             recent - value
    696 | |         }
        | |_________^ help: replace with `abs_diff`: `value.abs_diff(recent)`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_abs_diff

Signed-off-by: Uli Schlachter <psychon@znc.in>

Author: psychon

x11rb/src/xcb_ffi/mod.rs

@@ -688,13 +688,7 @@ fn reconstruct_full_sequence_impl(recent: SequenceNumber, value: u32) -> Sequenc
     ]
     .iter()
     .copied()
-    .min_by_key(|&value| {
-        if value > recent {
-            value - recent
-        } else {
-            recent - value
-        }
-    })
+    .min_by_key(|&value| value.abs_diff(recent))
     .unwrap();
     // Just because: Check that the result matches the passed-in value in the low bits
     assert_eq!(