buildGoModule: correct spelling in documentation and simplify the go-modules structure

doc/languages-frameworks/go.section.md

@@ -19,7 +19,7 @@ In the following is an example expression using `buildGoModule`, the following a
   To avoid updating this field when dependencies change, run `go mod vendor` in your source repo and set `vendorHash = null;`
 
   To obtain the actual hash, set `vendorHash = lib.fakeSha256;` and run the build ([more details here](#sec-source-hashes)).
-- `proxyVendor`: Fetches (go mod download) and proxies the vendor directory. This is useful if your code depends on c code and go mod tidy does not include the needed sources to build or if any dependency has case-insensitive conflicts which will produce platform dependant `vendorHash` checksums.
+- `proxyVendor`: Fetches (go mod download) and proxies the vendor directory. This is useful if your code depends on c code and go mod tidy does not include the needed sources to build or if any dependency has case-insensitive conflicts which will produce platform-dependent `vendorHash` checksums.
 - `modPostBuild`: Shell commands to run after the build of the go-modules executes `go mod vendor`, and before calculating fixed output derivation's `vendorHash` (or `vendorSha256`). Note that if you change this attribute, you need to update `vendorHash` (or `vendorSha256`) attribute.
 
 ```nix

pkgs/build-support/go/module.nix

@@ -54,7 +54,8 @@ assert (args' ? vendorHash && args' ? vendorSha256) -> throw "both `vendorHash`
 let
   args = removeAttrs args' [ "overrideModAttrs" "vendorSha256" "vendorHash" ];
 
-  go-modules = if (vendorHash != null) then stdenv.mkDerivation (let modArgs = {
+  go-modules = if (vendorHash == null) then "" else
+    (stdenv.mkDerivation {
 
     name = "${name}-go-modules";
 
@@ -138,13 +139,11 @@ let
     '';
 
     dontFixup = true;
-  }; in modArgs // (
-      {
-        outputHashMode = "recursive";
-        outputHash = vendorHash;
-        outputHashAlgo = if args' ? vendorSha256 || vendorHash == "" then "sha256" else null;
-      }
-  ) // overrideModAttrs modArgs) else "";
+
+    outputHashMode = "recursive";
+    outputHash = vendorHash;
+    outputHashAlgo = if args' ? vendorSha256 || vendorHash == "" then "sha256" else null;
+  }).overrideAttrs overrideModAttrs;
 
   package = stdenv.mkDerivation (args // {
     nativeBuildInputs = [ go ] ++ nativeBuildInputs;