Fix typo in encoding name

docs/errors.md

@@ -1,6 +1,6 @@
 # Known errors and limitations
 
-## uft-8 encoding only
+## utf-8 encoding only
 
 Trestle supports only utf8 as a file text-encoding. If non-utf8 files are encountered, errors will be reported / thrown.
 Trestle provides a [script](https://github.com/IBM/compliance-trestle/blob/develop/scripts/utf8me.py) that may be used to convert files to utf8 in a destructive manner that may change the file contents.