feat: Add `Diagnostic.reportToFile`

The code for reporting errors became quite verbose after writegate.
Reporting to stderr is very common, so this wrapper provides a default,
buffered way to report to a file.

1 files changed, 2 insertions, 4 deletions

diff --git a/example/simple.zig b/example/simple.zig
index ca6bd75..1834396 100644
--- a/example/simple.zig
+++ b/example/simple.zig
@@ -21,10 +21,8 @@ pub fn main() !void {
         .allocator = gpa.allocator(),
     }) catch |err| {
         // Report useful error and exit.
-        var buf: [1024]u8 = undefined;
-        var stderr = std.fs.File.stderr().writer(&buf);
-        try diag.report(&stderr.interface, err);
-        return stderr.interface.flush();
+        try diag.reportToFile(.stderr(), err);
+        return err;
     };
     defer res.deinit();