extract a variable

Dependencies

• [2] EAEGCJV5 rename
• [3] EGH7XDBK support non-text lines in Text.to2
• [4] KZ5GAYRP this fixes the immediate regression
• [*] BULPIBEG beginnings of a module for the text editor

Change contents

• edit in text.lua at line 873
  [2.192]

  [2.192]
  + local line_cache = State.line_cache[loc1.line]
• replacement in text.lua at line 875
  [2.251]→[2.251:394](∅→∅)
  − for i=#State.line_cache[loc1.line].screen_line_starting_pos,1,-1 do

  − local spos = State.line_cache[loc1.line].screen_line_starting_pos[i]
  [2.251]

  [2.394]
  + for i=#line_cache.screen_line_starting_pos,1,-1 do

  + local spos = line_cache.screen_line_starting_pos[i]