Warning: replacing invalid character code 159
line 1 column 1 - Warning: missing <!DOCTYPE> declaration
Info: Document content looks like HTML5
1 warning, 0 errors were found!

Character codes 128 to 159 (U+0080 to U+009F) are not allowed in HTML;
even if they were, they would likely be unprintable control characters.
Tidy assumed you wanted to refer to a character with the same byte value in the 
specified encoding and replaced that reference with the Unicode equivalent.

About HTML Tidy: https://github.com/htacg/tidy-html5
Bug reports and comments: https://github.com/htacg/tidy-html5/issues
Or send questions and comments to: https://lists.w3.org/Archives/Public/public-htacg/
Latest HTML specification: http://dev.w3.org/html5/spec-author-view/
Validate your HTML documents: http://validator.w3.org/nu/
Lobby your company to join the W3C: http://www.w3.org/Consortium