Doucment how raw-dylib finds DLLs at runtime

[FreddyDgh]

Was trying to use the 'raw-dylib' feature and found that things didn't quite work as I expected. Perhaps the following clarifications could be added to the docs?

• When using 'raw-dylib', where does Rust look for the DLLs at runtime?
• Can that lookup behavior be changed? For example, if I have the DLLs in a subdirectory instead of directly next to the executable, can I tell this to the compiler somehow?

reference/src/items/external-blocks.md

Lines 230 to 237 in effbdc1

	Specifying `kind = "dylib"` instructs the Rust compiler to link an import
	library based on the `name` key. The linker will then use its normal library
	resolution logic to find that import library. Alternatively, specifying
	`kind = "raw-dylib"` instructs the compiler to generate an import library
	during compilation and provide that to the linker instead.
	`raw-dylib` is only supported on Windows. Using it when targeting other
	platforms will result in a compiler error.

[bjorn3]

Windows doesn't support rpath, so you can't configure where dll's are looked up other than by changing PATH before starting the program. Windows will look for dll's right next to the executable as well as in all the directories referenced by PATH.