[FIX] spurious whitespace when saving unchanged blocks

With the new eyaml parser from I'm seeing the cipher text indented each time on the blocks you don't update

eyaml -i test_input.yaml

update a random key just to trigger a file diff on save, and diff, and notice the blocks are now more indented.

```
ciphertext = @cipher.gsub(/\n/, "\n" + @indentation)
```
```
+++ b/features/sandbox/test_input.yaml
@@ -1,33 +1,35 @@
 simple_string: how do you do
 encrypted_string: ENC[PKCS7,MIIBiQYJKoZIhvcNAQcDoIIBejCCAXYCAQAxggEhMIIBHQIBADAFMAACAQAwDQYJKoZIhvcNAQEBBQAEggEAgld+r
-encrypted_default_encryption_string: ENC[MIIBiQYJKoZIhvcNAQcDoIIBejCCAXYCAQAxggEhMIIBHQIBADAFMAACAQAwDQYJKoZIhvcNAQEB
+encrypted_default_encryption_string: ENC[PKCS7,MIIBiQYJKoZIhvcNAQcDoIIBejCCAXYCAQAxggEhMIIBHQIBADAFMAACAQAwDQYJKoZIhv

 simple_block: >
     once upon a time
     in a galaxy far far
     away
+    the original three
+    are the best

 encrypted_block: >
     ENC[PKCS7,MIIBiQYJKoZIhvcNAQcDoIIBejCCAXYCAQAxggEhMIIBHQIBADAFMAACAQAw
-    DQYJKoZIhvcNAQEBBQAEggEAYzeWn3MBLhOs4hokxMCWcDd9VuwCylQRUQ0w
-    KwCObeORw8PJkCDvi5ZIA2YkrvYTT6u3/7KfAiHd0Rg1WLb9et0Mg/Fd3DFF
-    7qhqOGHoQt3+4eKzlcikeR0/Lqrq2vTpqZ2Sw1CZ7Dn+Z4ll95p7lp97rb2J
-    kYTVroLYGWEcsS3JZLL4/l3z0bJbXNKKqJ1aHCAFq+wmWXeb6cDvvyHFg2N/
-    vGPFEQjP7AbWhxHxXDbYIGcU073u5NtE40JXL8SH82iHxqRF8s9g6Dh5cmjg
-    AY2pkBD9e6N78NNx+PAJswsFAV4DOCbXdf2BisyYbM3na35MVfyb6ggDegrE
-    ebOxxDBMBgkqhkiG9w0BBwEwHQYJYIZIAWUDBAEqBBCWeGlYS5cQoX78L6LK
-    /mczgCD/pI7usp1XPebnN8CngxHXuUjj5S+6IUpOW6l2JgUeWw==]
+            DQYJKoZIhvcNAQEBBQAEggEAYzeWn3MBLhOs4hokxMCWcDd9VuwCylQRUQ0w
+            KwCObeORw8PJkCDvi5ZIA2YkrvYTT6u3/7KfAiHd0Rg1WLb9et0Mg/Fd3DFF
+            7qhqOGHoQt3+4eKzlcikeR0/Lqrq2vTpqZ2Sw1CZ7Dn+Z4ll95p7lp97rb2J
```
^^^^^^^^^ indent grows each save