no longer silently add RTS to asmsubs that don't have one

docs/source/compiling.rst

@@ -182,6 +182,12 @@ One or more .p8 module files
     interpret certain instructions differently and produce unexpected opcodes (like LDA X getting
     turned into TXA, or not, depending on the symbol 'x' being defined in your own assembly code or not)
 
+``-addmissingrts``
+    Enables old compiler behavior that silently adds RTS to asmsubs that don't have one.
+    This was done to fix asmsubs so they return properly to the caller instead of crashing the program.
+    However the new compiler behavior is to not silently modify the code anymore and instead give an error message
+    that tells you how to fix the problem. This option may go away in future version.
+
 ``-quietasm``
     Don't print assembler output results.
 

docs/source/todo.rst

@@ -1,6 +1,8 @@
 TODO
 ====
 
+- check benchmark score vs previous version
+
 Improve register load order in subroutine call args assignments:
 in certain situations, the "wrong" order of evaluation of function call arguments is done which results
 in overwriting registers that already got their value, which requires a lot of stack juggling (especially on plain 6502 cpu!)
@@ -11,7 +13,6 @@ Future Things and Ideas
 ^^^^^^^^^^^^^^^^^^^^^^^
 - Improve the SublimeText syntax file for prog8, you can also install this for 'bat': https://github.com/sharkdp/bat?tab=readme-ov-file#adding-new-syntaxes--language-definitions
 - Can we support signed % (remainder) somehow?
-- Don't add "random" rts to %asm blocks but instead give a warning about it? (but this breaks existing behavior that others already depend on... command line switch? block directive?)
 - IR: implement missing operators in AssignmentGen  (array shifts etc)
 - instead of copy-pasting inline asmsubs, make them into a 64tass macro and use that instead.
   that will allow them to be reused from custom user written assembly code as well.