os/linux.rb: wsl_version: apply suggestions from code review

Co-authored-by: Mike McQuaid <mike@mikemcquaid.com>

Library/Homebrew/os/linux.rb

@@ -35,16 +35,20 @@ module OS
 
     sig { returns(Version) }
     def wsl_version
-      Version::NULL unless wsl?
+      return Version::NULL unless wsl?
-      kernel = OS.kernel_version.to_s
-      return Version.new("2 (Microsoft Store)") if Version.new(T.must(kernel[/^([0-9.]*)-.*/,
-                                                                             1])) > Version.new("5.15")
-      return Version.new("2") if kernel.include?("-microsoft")
-      return Version.new("1") if kernel.include?("-Microsoft")
 
+      kernel = OS.kernel_version.to_s
+      if Version.new(T.must(kernel[/^([0-9.]*)-.*/, 1])) > Version.new("5.15")
+        Version.new("2 (Microsoft Store)")
+      elsif kernel.include?("-microsoft")
+        Version.new("2")
+      elsif kernel.include?("-Microsoft")
+        Version.new("1")
+      else
         Version::NULL
       end
     end
+  end
 
   # rubocop:disable Style/Documentation
   module Mac