(\codeunder): Use \_ and \ifusingtt to avoid dotaccent from _ in roman fonts, e.g...

(\codeunder): Use \_ and \ifusingtt to avoid dotaccent from _ in roman fonts, e.g., @deftypefn.

(\codeunder): Use \_ and \ifusingtt to avoid dotaccent from _ in roman
fonts, e.g., @deftypefn.
(\tex): Remove spurious spaces at the end of subdefinitions.
From: "John W. Eaton" <jwe@bevo.che.wisc.edu>.
(\url, \email): \let to \code; no quotes or angle brackets.

From-SVN: r14099