bugfix: cursor past end of screen line

Dependencies

• [2] 5L7K4GBD clicking to the right of a wrapped line
• [3] BOFNXP5G clicking now moves the cursor even on long, wrapped lines
• [*] BULPIBEG beginnings of a module for the text editor

Change contents

• replacement in text.lua at line 305
  [2.437]→[2.437:513](∅→∅)
  − Cursor_pos = line.screen_line_starting_pos[screen_line_index+1] - 1
  [2.437]

  [2.513]
  + Cursor_pos = line.screen_line_starting_pos[screen_line_index+1]