chore: fix typos (#17670)

Co-authored-by: zeertzjq <zeertzjq@outlook.com>

src/nvim/terminal.c

@@ -1288,7 +1288,7 @@ static bool send_mouse_event(Terminal *term, int c)
     return mouse_win == curwin;
   }
 
-  // ignore left release action if it was not proccessed above
+  // ignore left release action if it was not processed above
   // to prevent leaving Terminal mode after entering to it using a mouse
   if (c == K_LEFTRELEASE && mouse_win->w_buffer->terminal == term) {
     return false;