Remove trailing whitespace that was accidently added to std.file tempDir.

std/file.d

@@ -5280,7 +5280,7 @@ string tempDir() @trusted
     {
         import std.path : dirSeparator;
         import std.algorithm.searching : endsWith;
-        
+
         // It is very rare a directory path will reach this point with a directory seperator at the end
         // However on OSX this can happen, so we must verify least we break user code i.e. https://github.com/dlang/dub/pull/2208
         if (!input.endsWith(dirSeparator))
@@ -5288,7 +5288,7 @@ string tempDir() @trusted
         else
             return input;
     }
-    
+
     static string cache;
     if (cache is null)
     {