Missing AArch64 Doxygen INSTR_CREATE_ docs cause build failure

Split from #1569

With a new doxygen 1.8.17 the missing AArch64 headers cause build failure:

```
CMake Error at api/docs/CMake_rundoxygen.cmake:143 (message):
*** doxygen failed: ***

D:/derek/dr/git/build_x64_dbg_tests/include/dr_ir_macros_aarch64.h:501:
warning: The following parameters of INSTR_CREATE_adc(dc, Rd, Rn, Rm) are
not documented:

parameter 'Rd'
parameter 'Rn'
parameter 'Rm'

D:/derek/dr/git/build_x64_dbg_tests/include/dr_ir_macros_aarch64.h:503:
warning: The following parameters of INSTR_CREATE_adcs(dc, Rd, Rn, Rm) are
not documented:

parameter 'Rd'
parameter 'Rn'
parameter 'Rm'

D:/derek/dr/git/build_x64_dbg_tests/include/dr_ir_macros_aarch64.h:433:
warning: The following parameters of INSTR_CREATE_add(dc, rd, rn,
rm_or_imm) are not documented:

parameter 'rd'
parameter 'rn'
parameter 'rm_or_imm'

D:/derek/dr/git/build_x64_dbg_tests/include/dr_ir_macros_aarch64.h:435:
warning: The following parameters of INSTR_CREATE_add_extend(dc, rd, rn,
rm, ext, exa) are not documented:

parameter 'rd'
parameter 'rn'
parameter 'rm'
parameter 'ext'
parameter 'exa'

...
```

I don't want to disable all such warnings because they are very useful (there were a couple of x86 ones I am fixing now as part of PR #4105). There seems to be no way to disable warnings for just one file. Maybe the best way forward is to disable these macros from appearing in the generating HTML docs at all, until their headers are added.