Better documentation for linking dynamic libraries
### Description

[arithmetic_geometric_mean_calculate_pi.txt](https://github.com/user-attachments/files/18759004/arithmetic_geometric_mean_calculate_pi.txt) Rename to .nim cause GitHub sux too.

Compile this sucker with this on a current version of macOS:

nim --verbosity:2 -d:nimDebugDlOpen c arithmetic_geometric_mean_calculate_pi.nim

and you'll get:

./arithmetic_geometric_mean_calculate_pi
dlopen(libgmp.dylib, 0x0002): tried: 'libgmp.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OSlibgmp.dylib' (no such file), '/usr/lib/libgmp.dylib' (no such file, not in dyld cache), 'libgmp.dylib' (no such file)
could not load: libgmp.dylib

You will never find a library like gmp in /usr/lib due to SIP. https://support.apple.com/en-us/102149

It should be made clear in support documentation or other changes should be made such that a compile command like this is clearly needed:

nim --verbosity:3 --dynlibOverride:gmp --passL:"-L/opt/local/lib -lgmp" c arithmetic_geometric_mean_calculate_pi.nim

Don't forget to nimble install bignum.

### Nim Version

nim -v
Nim Compiler Version 1.6.14 [MacOSX: arm64]
Compiled at 2023-07-14
Copyright (c) 2006-2023 by Andreas Rumpf

active boot switches: -d:release

### Current Output

```text

```

### Expected Output

```text

```

### Known Workarounds

_No response_

### Additional Information

_No response_