added details to windows installation (mlc-ai#1133)

32bit version of the zstd.dll library was causing issues, so updated the doc to be more specific and download the 64bit version.

docs/install/mlc_llm.rst

@@ -124,10 +124,10 @@ Select your operating system/compute platform and run the command in your termin
 
                 FileNotFoundError: Could not find module 'path\to\site-packages\tvm\tvm.dll' (or one of its dependencies). Try using the full path with constructor syntax.
 
-            It is likely `zstd`, a dependency to LLVM, was missing. Please `download <https://github.com/facebook/zstd/releases/tag/v1.5.5>`__ the precompiled binary, rename it to `zstd.dll` and copy to the same folder as `tvm.dll`.
+            It is likely `zstd`, a dependency to LLVM, was missing. Please `download <https://github.com/facebook/zstd/releases/tag/v1.5.5>`__ the 64 bit version of precompiled binary, rename it to `zstd.dll` and copy to the same folder as `tvm.dll`.
 
 
 Option 2. Build from Source
 ---------------------------
 
-Upcoming.
+Upcoming.