Fix code excerpts in the docs that point at the wrong lines

[pvcraven]

Summary

Docs only. Fixes 62 code excerpts whose :emphasize-lines: or :lines: pointed at the wrong code: 48 in tutorials and 14 on example pages. The example code had changed since their line numbers were set. Some had been wrong for years: the background image example last highlighted the right lines in 2021.

How the numbers were found

For each literalinclude with :lines: or :emphasize-lines: (about 180):

1. The commit that set its numbers: found by searching the history for that spec. This follows the move from doc/examples to doc/example_code.
2. Remap to now: each referenced line is mapped from the file as it was in that commit to the file today, with a line diff.
3. Compare the highlighted text then and now:
   • Same text (24 excerpts): accepted.
   • Reformatted or updated code (for example on_update → update, Optional[X] → X | None, a wrapped call): checked by hand and accepted. Most of the rest are like this.
   • Rewritten code: ranges chosen by hand to highlight the code that does the same job now:
     • sprite_collect_coins_background: loading and drawing the background.
     • sprite_face_left_or_right: the left/right textures and switching between them.
     • sprite_move_scrolling_shake: the ScreenShake2D setup, update, start and readjust (it used to be one block of manual shake code).
     • sprite_explosion_bitmapped: the old explosions_list setup line is now explosions_list.clear() in reset().
4. A boundary check on every include: flags ranges that start or end partway through a statement, or stop before an elif/else of a block they started. I looked at each flagged one in context. The 14 still flagged are deliberate: one argument of a call, the body of a loop, GLSL lines inside a shader string, or one branch of an if/elif.

Already wrong when they were written

• camera2d_splitscreen: off by about a line since it was added in Add a split screen example using Camera2D #2789 (for example, it cut the super().__init__() call in half). It now highlights the camera code: window size, setup_players_cameras, zoom keys and methods, centering, on_draw and on_resize.
• sprite_rotate_around_point: started on a closing ]) and stopped before the platform rotation. It now highlights the method and all of on_update.
• shader_toy_glow step 3: one line off.
• Pymunk tutorial, "Add Ladders - Game Window On Update":
  • Its :lines: started in the middle of the bullet code in on_mouse_press.
  • It now uses :pyobject: GameWindow.on_update with :lines: 1-41, highlighting the ladder checks and the up/down branches.
  • Since it selects the method by name, it can't drift again.

Checks

• Docs build: sphinx-build produces no literalinclude or line-range warnings.
• Recent PRs: Fix the ruff errors in the tests #2939–Make mypy and pyright fail CI, and fix their errors #2942 didn't cause any of this. Their changes kept every line-referenced file's line count the same.
• Prose: no rst text refers to code line numbers.

The changelog has an entry under Unreleased → Misc Changes.

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