mdbook: remove clangarm64 workaround

mingw-w64-mdbook/PKGBUILD

@@ -20,24 +20,7 @@ sha256sums=('fece3b1c3875ab6f99cd9bc98c131a751bf4255bdbe364522512247d105092c0')
 prepare() {
   cd "${srcdir}/${_realName}-${pkgver}"
 
-  cargo vendor \
-    --locked \
-    --versioned-dirs
-
-  mkdir -p .cargo
-  cat >> .cargo/config.toml <<END
-[source.crates-io]
-replace-with = "vendored-sources"
-
-[source.vendored-sources]
-directory = "vendor"
-END
-
-
-  sed -i -e 's/"cfg(all(target_arch = \\"\([^\\]\+\)\\", target_env = \\"gnu\\", target_abi = \\"llvm\\", not(windows_raw_dylib)))"/"\1-pc-windows-gnullvm"/g' \
-    "vendor/windows-targets-0.48.1/Cargo.toml"
-  sed -i -e 's/\("Cargo.toml":\)"[^"]\+"/\1"'"$(sha256sum "vendor/windows-targets-0.48.1/Cargo.toml" | cut -d' ' -f1)"'"/' \
-    "vendor/windows-targets-0.48.1/.cargo-checksum.json"
+  cargo fetch --locked
 }
 
 build() {