Update encoding/README.md

Co-authored-by: Sam Sneddon <me@gsnedders.com>

Author: sideshowbarker

encoding/README.md

@@ -34,6 +34,6 @@ machine and tree-construction stage defined in the spec.
 
 For all tests outside the subdirectory named "preparsed", the encoding name
 indicated is instead the expected character encoding for the output after
-fully parsing the given test data; that is, it’s the expected character
+fully parsing the given test data; that is, it's the expected character
 encoding for the output after running the tokenization state machine and
 tree-construction stage.