move caching behavior inside compute_fragments

Dependencies

• [2] OYVFFWBK move
• [3] ZDAJXYIX remove some unnecessary work
• [4] 5DOC2CBM extract a function
• [5] ILOA5BYF separate data structure for each line's cache data
• [6] XUGDTYW2 stop confusingly reading a global
• [7] X3F7ECSL add state arg to some functions
• [8] HVJKBW5U drop some unnecessary calls
• [9] H2DPLWMV snapshot: wrapping long lines at word boundaries
• [*] BULPIBEG beginnings of a module for the text editor
• [*] HGC5RGJP switch to line index in a function
• [*] TGHAJBES use line cache for drawings as well

Change contents

• replacement in text.lua at line 21
  [4.47]→[3.3:93](∅→∅)
  − if line_cache.fragments == nil then

  − Text.compute_fragments(State, line_index)

  − end
  [4.47]

  [4.3860]
  + Text.compute_fragments(State, line_index)
• replacement in text.lua at line 91
  [2.309]→[2.309:399](∅→∅)
  − if line_cache.fragments == nil then

  − Text.compute_fragments(State, line_index)

  − end
  [2.309]

  [2.399]
  + Text.compute_fragments(State, line_index)
• edit in text.lua at line 112
  [12.186]

  [13.54]
  + if line.mode ~= 'text' then return end
• edit in text.lua at line 114
  [13.104]

  [4.3962]
  + if line_cache.fragments then

  + return

  + end