A pattern anchoring some alternatives with ^ and not others is refused with why, not a bare bad regular expression

`^def|x` and `foo$|^zèbre` were refused with a bare "bad regular expression",
the same words as a syntax error, so a script could not tell what to change.
They now say "an alternation anchors every branch with ^ or none (^a|^b, not
^a|b)", through addr and Edit alike. fs.md states the rule and that a `$`
does not count toward it (`foo$|bar` is fine).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/sam_edit.zig b/src/sam_edit.zig
index 0f317a83..94cf6fe0 100644
--- a/src/sam_edit.zig
+++ b/src/sam_edit.zig
@@ -463,6 +463,7 @@ const Exec = struct {
             error.TooLong => fail(ex.why, "{s}", .{regexp.Regex.e_long}),
             error.WideRange => fail(ex.why, "{s}", .{regexp.Regex.e_wide}),
             error.NegatedRunes => fail(ex.why, "{s}", .{regexp.Regex.e_negated}),
+            error.Mixed => fail(ex.why, "{s}", .{regexp.Regex.e_mixed}),
             error.Bad => fail(ex.why, "bad regexp in {c} command", .{c}),
         };
     }