lib.strings: Dont create scopes for getName/getVersion

We can create the `parse` function in a scope one level up to avoid recomputing it every time.

lib/strings.nix

@@ -715,12 +715,12 @@ rec {
        getName pkgs.youtube-dl
        => "youtube-dl"
   */
-  getName = x:
-   let
-     parse = drv: (parseDrvName drv).name;
-   in if isString x
-      then parse x
-      else x.pname or (parse x.name);
+  getName = let
+    parse = drv: (parseDrvName drv).name;
+  in x:
+    if isString x
+    then parse x
+    else x.pname or (parse x.name);
 
   /* This function takes an argument that's either a derivation or a
      derivation's "name" attribute and extracts the version part from that
@@ -732,12 +732,12 @@ rec {
        getVersion pkgs.youtube-dl
        => "2016.01.01"
   */
-  getVersion = x:
-   let
-     parse = drv: (parseDrvName drv).version;
-   in if isString x
-      then parse x
-      else x.version or (parse x.name);
+  getVersion = let
+    parse = drv: (parseDrvName drv).version;
+  in x:
+    if isString x
+    then parse x
+    else x.version or (parse x.name);
 
   /* Extract name with version from URL. Ask for separator which is
      supposed to start extension.