rustfmt: update expected Rust edition
In this case it doesn't change anything, but we've been using 2021 for a
while now.
#ifndef HG_BDIFF_H
#define HG_BDIFF_H
#include "compat.h"
struct bdiff_line {
int hash, n, e;
ssize_t len;
const char *l;
};
struct bdiff_hunk;
struct bdiff_hunk {
int a1, a2, b1, b2;
struct bdiff_hunk *next;
};
int bdiff_splitlines(const char *a, ssize_t len, struct bdiff_line **lr);
int bdiff_diff(struct bdiff_line *a, int an, struct bdiff_line *b, int bn,
struct bdiff_hunk *base);
void bdiff_freehunks(struct bdiff_hunk *l);
#endif