The closing single quote needs to be indented...

if it's on its own line.

```
% cd libyaml
% echo "+STR
+DOC
+SEQ
=VAL '\\\n
-SEQ
-DOC
-STR" | ./tests/run-emitter-test-suite
- '

'
% # fix
% make
...

% echo "+STR
+DOC
+SEQ
=VAL '\\\n
-SEQ
-DOC
-STR" | ./tests/run-emitter-test-suite
- '

  '
```

src/emitter.c

@@ -2001,6 +2001,9 @@
         }
     }
 
+    if (breaks)
+        if (!yaml_emitter_write_indent(emitter)) return 0;
+
     if (!yaml_emitter_write_indicator(emitter, "'", 0, 0, 0))
         return 0;