Pokemon Emerald: Add exhaustive list of ROM changes (#2801)

worlds/pokemon_emerald/docs/rom changes.md

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+## QoL
+
+- The catch tutorial and cutscenes during your first visit to Petalburg are skipped
+- The match call tutorial after you leave Devon Corp is skipped
+- Cycling and running is allowed in every map (some exceptions like Fortree and Pacifidlog)
+- When you run out of Repel steps, you'll be prompted to use another one if you have more in your bag
+- Text is always rendered in its entirety on the first frame (instant text)
+- With an option set, text will advance if A is held
+- The message explaining that the trainer is about to send out a new pokemon is shortened to fit on two lines so that
+you can still read the species when deciding whether to change pokemon
+- The Pokemon Center Nurse dialogue is entirely removed except for the final text box
+- When receiving TMs and HMs, the move that it teaches is consistently displayed in the "received item" message (by
+default, certain ways of receiving items would only display the TM/HM number)
+- The Pokedex starts in national mode
+- The Oldale Pokemart sells Poke Balls at the start of the game
+- Pauses during battles (e.g. the ~1 second pause at the start of a turn before an opponent uses a potion) are shorter
+by 62.5%
+- The sliding animation for trainers and wild pokemon at the start of a battle runs at double speed.
+- Bag space was greatly expanded (there is room for one stack of every unique item in every pocket, plus a little bit
+extra for some pockets)
+  - Save data format was changed as a result of this. Shrank some unused space and removed some multiplayer phrases from
+  the save data.
+  - Pretty much any code that checks for bag space is ignored or bypassed (this sounds dangerous, but with expanded bag
+  space you should pretty much never have a full bag unless you're trying to fill it up, and skipping those checks
+  greatly simplifies detecting when items are picked up)
+- Pokemon are never disobedient
+- When moving in the overworld, set the input priority based on the most recently pressed direction rather than by some
+predetermined priority
+- Shoal cave changes state every time you reload the map and is no longer tied to the RTC
+- Increased safari zone steps from 500 to 50000
+- Trainers will not approach the player if the blind trainers option is set
+- Changed trade evolutions to be possible without trading:
+  - Politoed: Use King's Rock in bag menu
+  - Alakazam: Level 37
+  - Machamp: Level 37
+  - Golem: Level 37
+  - Slowking: Use King's Rock in bag menu
+  - Gengar: Level 37
+  - Steelix: Use Metal Coat in bag menu
+  - Kingdra: Use Dragon Scale in bag menu
+  - Scizor: Use Metal Coat in bag menu
+  - Porygon2: Use Up-Grade in bag menu
+  - Milotic: Level 30
+  - Huntail: Use Deep Sea Tooth in bag menu
+  - Gorebyss: Use Deep Sea Scale in bag menu
+
+## Game State Changes/Softlock Prevention
+
+- Mr. Briney never disappears or stops letting you use his ferry
+- Prevent the player from flying or surfing until they have received the Pokedex
+- The S.S. Tidal will be available at all times if you have the option enabled
+- Some NPCs or tiles are removed on the creation of a new save file based on player options
+- Ensured that every species has some damaging move by level 5
+- Route 115 may have strength boulders between the beach and cave entrance based on player options
+- The Petalburg Gym is set up based on your player options rather than after the first 4 gyms
+- The E4 guards will actually check all your badges (or gyms beaten based on your options) instead of just the Feather
+Badge
+- Steven cuts the conversation short in Granite Cave if you don't have the Letter
+- Dock checks that you have the Devon Goods before asking you to deliver them (and thus opening the museum)
+- Rydel gives you both bikes at the same time
+- The man in Pacifidlog who gives you Frustration and Return will give you both at the same time, does not check
+friendship first, and no longer has any behavior related to the RTC
+- The woman who gives you the Soothe Bell in Slateport does not check friendship
+- When trading the Scanner with Captain Stern, you will receive both the Deep Sea Tooth and Deep Sea Scale
+
+## Misc
+
+- You can no longer try to switch bikes in the bike shop
+- The Seashore House only rewards you with 1 Soda Pop instead of 6
+- Many small changes that make it possible to swap single battles to double battles
+  - Includes some safeguards against two trainers seeing you and initiating a battle while one or both of them are
+  "single trainer double battles"
+- Game now properly waits on vblank instead of spinning in a while loop
+- Misc small changes to text for consistency
+- Many bugfixes to the vanilla game code