File r38/help/mkhelpu.sed artifact 1fc88e5ba8 part of check-in b5833487d7

s/Euler's/Euler/g
s/EULER'S/EULER/g
s/Euler constant can/Euler's constant can/g
s/Catalan's/Catalan/g
s/CATALAN'S/CATALAN/g
s/Khinchin's/Khinchin/g
s/KHINCHIN'S/KHINCHIN/g
s/Khinchin book/Khinchin's book/g
s/Jacobi's/Jacobi/g
s/\@\$/\$/g
s/\@key/(Key)/g
s/\@\%/\%/g
s/\@\_/\_/g