xz: Avoid the abbreviation "e.g." on the man page.

xz: Avoid the abbreviation "e.g." on the man page.

A few are simply omitted, most are converted to "for example"
and surrounded with commas. Sounds like that this is better
style, for example, man-pages(7) recommends avoiding such
abbreviations except in parenthesis.

Thanks to Bjarni Ingi Gislason.