Fix typos in policies.json code snippet areas

-updated EnableTrackingProtection policies.json code snippet (missing closing brace)
-updated EncryptedMediaExtensions policies.json code snippet (missing closing brace)
-updated PSFjs policies.json code snippet (missing closing brace)
-updated PictureInPicture policies.json code snippet (replaced comma between true and false with pipe to match styling throughout document)
-updated Proxy policies.json code snippet (missing comma at the end of "SOCKSVersion")