std: Restore conventional `compareFn` behavior for `binarySearch`

PR #20927 made some improvements to the `binarySearch` API, but one
change I found surprising was the relationship between the left-hand and
right-hand parameters of `compareFn` was inverted. This is different
from how comparison functions typically behave, both in other parts of
Zig (e.g. `std.math.order`) and in other languages (e.g. C's `bsearch`).
Unless a strong reason can be identified and documented for doing
otherwise, I think it'll be better to stick with convention.

While writing this patch and changing things back to the way they were,
the predicates of `lowerBound` and `upperBound` seemed to be the only
areas that benefited from the inversion. I don't think that benefit is
worth the cost, personally. Calling `Order.invert()` in the predicates
accomplishes the same goal.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/compiler/aro/aro/Preprocessor.zig b/lib/compiler/aro/aro/Preprocessor.zig
index a8eb74a4a8..5a03cc0dff 100644
--- a/lib/compiler/aro/aro/Preprocessor.zig
+++ b/lib/compiler/aro/aro/Preprocessor.zig
@@ -271,7 +271,7 @@ fn clearBuffers(pp: *Preprocessor) void {
 pub fn expansionSlice(pp: *Preprocessor, tok: Tree.TokenIndex) []Source.Location {
     const S = struct {
         fn orderTokenIndex(context: Tree.TokenIndex, item: Tree.TokenIndex) std.math.Order {
-            return std.math.order(item, context);
+            return std.math.order(context, item);
         }
     };