[Inkscape-translator] Update Windows installer translation wiki info

The info om http://wiki.inkscape.org/wiki/index.php/Interface_translation#Windows_instal... seems not to match the content of the translation files.

I dont see this in the translation file: !insertmacro MUI_LANGUAGE "English" ${LANG_ENGLISH}

Also the part that says: "Change header information in yourlanguage.nsh file, like "windows code page" and "Authors" to proper values."

I would suggest to add link for "windows code page" so people can find what code to use for theyr language.