Documentation: Update low level changes document

docs/jgrpp-low-level-changes.md

@@ -19,6 +19,7 @@ This document does not describe the player-visible changes/additions described i
 * Emit a "crash" log, savegame and screenshot on multiplayer desync.
 * Add crash/desync information to output screenshot and savegame files.
 * Multiplayer server and client exchange desync logs after a desync occurs.
+* Multiplayer clients send state hashes and random values since the last sync to the server after a desync, to identify which frame first diverged.
 * Decrease sync frame period when desync occurs.
 
 #### Assertions
@@ -75,8 +76,7 @@ This document does not describe the player-visible changes/additions described i
 * Various data structures have been replaced with B-tree maps/sets (cpp-btree library).
 * Various lists have been replaced with vectors or deques, etc.
 * Remove mutexes from SmallStack, only used from the main thread.
-* Use std::string in CommandContainer instead of a giant static buffer.
-* Add a third parameter p3 to DoCommand/CommandContainer.
+* Add a third parameter p3, and an auxiliary data mechanism to DoCommand/CommandContainer.
 * Add a free bitmap for pool slots.
 * Maintain free list for text effect entries.
 * Many fields have been widened.
@@ -91,6 +91,7 @@ This document does not describe the player-visible changes/additions described i
 * Add vehicle flag to mark the last vehicle in a consist with a visual effect.
 * Index the vehicle list in per type arrays for use by CallVehicleTicks.
 * Cache whether the vehicle should be drawn.
+* Pre-compute engine refit capacity callbacks if possible.
 
 ### Network/multiplayer
 
@@ -113,8 +114,10 @@ This document does not describe the player-visible changes/additions described i
 * Various forms of caching and incremental updates to the link graph overlay.
 * Change FlowStat from an RB-tree to a flat map with small-object optimisation.
 * Change FlowStatMap from an RB-tree to a B-tree indexed vector.
+* Change LinkGraph::EdgeMatrix to a sparse storage format.
 * Replace MCF Dijkstra RB-tree with B-tree.
 * Reduce performance issues when deleting stale links with refit to any cargo.
+* Dynamically adjust accuracy parameters in MCF 1st pass to avoid computing large numbers of excessively small flows.
 
 ### Pathfinder
 
@@ -147,6 +150,8 @@ This document does not describe the player-visible changes/additions described i
 * Apply many optimisations to VarAction2 deterministic sprite groups.
 * Avoid making callbacks which can be pre-determined to be unhandled, or which can be statically determined ahead of time.
 * Avoid animating industry tiles which are not actually animated in the current layout.
+* Setting the animation frame to its current value no longer triggers a redraw.
+* Animation is not started if it can be determined that it would stop immediately.
 * Avoid unnecessarily triggering or redrawing NewGRF houses.
 
 ### SDL2
@@ -182,3 +187,4 @@ This document does not describe the player-visible changes/additions described i
 * Change inheritance model of class Window to keep UndefinedBehaviorSanitizer happy.
 * Various other misc changes and fixes to reduce UndefinedBehaviorSanitizer and ThreadSanitizer spam.
 * Add a chicken bits setting, just in case.
+