LibLine: Add a setter for the cursor position

Author: https://github.com/alimpfard
Commit: 2d7aaab897
Pull-request: https://github.com/SerenityOS/serenity/pull/3505
Reviewed-by: https://github.com/awesomekling
Reviewed-by: https://github.com/devsh0

Libraries/LibLine/Editor.h

@@ -204,6 +204,12 @@ public:
     }
 
     size_t cursor() const { return m_cursor; }
+    void set_cursor(size_t cursor)
+    {
+        if (cursor > m_buffer.size())
+            cursor = m_buffer.size();
+        m_cursor = cursor;
+    }
     const Vector<u32, 1024>& buffer() const { return m_buffer; }
     u32 buffer_at(size_t pos) const { return m_buffer.at(pos); }
     String line() const { return line(m_buffer.size()); }