Move `+1` to appropriate location

lib/src/core/tabs.dart

@@ -18,13 +18,13 @@ class TabStops {
     }
   }
 
-  /// Finds the next tab stop between [start] and [end].
+  /// Finds the next tab stop index, which satisfies [start] <= index < [end].
   int? find(int start, int end) {
     if (start >= end) {
       return null;
     }
     end = min(end, _stops.length);
-    for (var i = start + 1; i < end; i++) {
+    for (var i = start; i < end; i++) {
       if (_stops[i]) {
         return i;
       }

lib/src/terminal.dart

@@ -396,7 +396,7 @@ class Terminal with Observable implements TerminalState, EscapeHandler {
 
   @override
   void tab() {
-    final nextStop = _tabStops.find(_buffer.cursorX, _viewWidth);
+    final nextStop = _tabStops.find(_buffer.cursorX + 1, _viewWidth);
 
     if (nextStop != null) {
       _buffer.setCursorX(nextStop);