tr2/lara/col: fix right backwards step frame range

This fixes the frame range used to test if Lara should step off a step
backwards with her right foot.

Resolves  #1602.

docs/tr2/CHANGELOG.md

@@ -1,6 +1,7 @@
 ## [Unreleased](https://github.com/LostArtefacts/TRX/compare/tr2-0.8...develop) - ××××-××-××
 - added Linux builds and toolchain (#1598)
 - fixed Lara activating triggers one frame too early (#2205, regression from 0.7)
+- fixed Lara never stepping backwards off a step using her right foot (#1602)
 
 ## [0.8](https://github.com/LostArtefacts/TRX/compare/tr2-0.8...tr2-0.8) - 2025-01-01
 - completed decompilation efforts – TR2X.dll is gone, Tomb2.exe no longer needed (#1694)

docs/tr2/README.md

@@ -55,6 +55,7 @@ game with new enhancements and features.
 - fixed Lara prioritising throwing a spent flare while mid-air, so to avoid missing ledge grabs
 - fixed Lara at times not being able to jump immediately after going from her walking to running animation
 - fixed looking forward too far causing an upside down camera frame
+- fixed Lara never stepping backwards off a step using her right foot
 - fixed the following floor data issues:
     - **Opera House**: fixed the trigger under item 203 to trigger it rather than item 204
     - **Wreck of the Maria Doria**: fixed room 98 not having water

src/tr2/game/lara/col.c

@@ -31,8 +31,8 @@
 #define LF_RUN_R_FOOT_GROUND 14
 #define LF_RUN_R_END 21
 
-#define LF_BACK_R_START 964
-#define LF_BACK_R_END 993
+#define LF_BACK_R_START 26
+#define LF_BACK_R_END 55
 
 #define LF_WADE_L_START 0
 #define LF_WADE_L_END 9