Compilation: point caret in error message at the main token

test/compile_errors.zig

@@ -174,6 +174,15 @@ pub fn addCases(ctx: *TestContext) !void {
         });
     }
 
+    {
+        const case = ctx.obj("missing semicolon at EOF", .{});
+        case.addError(
+            \\const foo = 1
+        , &[_][]const u8{
+            \\:1:14: error: expected ';' after declaration
+        });
+    }
+
     // TODO test this in stage2, but we won't even try in stage1
     //ctx.objErrStage1("inline fn calls itself indirectly",
     //    \\export fn foo() void {