Updated and fixed ReplaceMethod

[SokyranTheDragon]

• The opcode of replaced method is based on the new method, rather than the one it replaces
• Added extraInstructionsAfter argument to insert instructions after the targeted code instruction
• The extraInstructions argument was renamed to extraInstructionsBefore
• Made the method replacement (and the argument for it) optional
  • The method can now be used to insert extra instructions before/after the targeted method without replacing it
• An exception will be thrown if the IEnumerable<CodeInstruction> is null
  • It feels like the best course of action, as not doing anything will cause an exception later on and returning anything (or nothing) could have an unexpected consequences
• An error will be displayed if the method was provided a null target method
• An error will be displayed if the method was not provided a replacement method or a function to insert extra instructions
• Updated the compat for "A RimWorld of Magic" to support the new method signature