fix: render cursor correctly in case the same character remains the cursor position

src/render.zig

@@ -96,12 +96,18 @@ pub const Buffered = struct {
                 const idx = (row * this.size.x) + col;
                 const cs = s[idx];
                 const cvs = vs[idx];
-                if (cs.eql(cvs)) continue;
 
-                if (cvs.style.cursor) cursor_position = .{
+                // update the latest found cursor position
+                if (cvs.style.cursor) {
+                    assert(cursor_position == null);
+                    cursor_position = .{
                         .x = @truncate(col),
                         .y = @truncate(row),
                     };
+                }
+
+                if (cs.eql(cvs)) continue;
+
                 // render differences found in virtual screen
                 try terminal.setCursorPosition(.{ .y = @truncate(row), .x = @truncate(col) });
                 try cvs.value(writer);
@@ -118,6 +124,7 @@ pub const Buffered = struct {
 
 const std = @import("std");
 const meta = std.meta;
+const assert = std.debug.assert;
 const Allocator = std.mem.Allocator;
 const terminal = @import("terminal.zig");
 const Cell = @import("cell.zig");