Remove constant tag from literal values

[haszi]

Replace <constant> tags with <literal> tags for literals which are mostly one of the following:

• strings
• format placeholders
• array keys
• numbers (integers, floats, hexadecimals and numers using scientific (e) notation)

[haszi]

These changes were made with the following script:

#!/bin/bash
sed -i -E 's/<constant>(%.)<\/constant>/<literal>\1<\/literal>/g' install/fpm/configuration.xml
sed -i -E "s/<constant>'<\/constant>/<literal>'<\/literal>/g" reference/cubrid/cubridmysql/cubrid-real-escape-string.xml
sed -i -E 's/<constant>\.\.<\/constant>/<literal>\.\.<\/literal>/g' reference/ev/evstat.xml
sed -i -E "s/<constant>'(.+)'<\/constant>/<literal>'\1'<\/literal>/g" reference/ev/evstat.xml
sed -i -E "s/<constant>'(.+)'<\/constant>/<literal>'\1'<\/literal>/g" reference/ev/evstat/attr.xml
sed -i -E "s/<constant>'ndots'<\/constant>/<parameter>'ndots'<\/parameter>/g" reference/event/eventdnsbase/setsearchndots.xml
sed -i -E 's/<constant>"ctr"<\/constant>/<literal>"ctr"<\/literal>/g' reference/mcrypt/constants.xml
sed -i -E 's/<constant>"ncfb"<\/constant>/<literal>"ncfb"<\/literal>/g' reference/mcrypt/constants.xml
sed -i -E 's/<constant>(\\.{1})<\/constant>/<literal>\1<\/literal>/g' reference/sockets/functions/socket-read.xml
sed -i -E 's/<constant>\&amp;<\/constant>/<literal>\&amp;<\/literal>/g' reference/dom/domattr.xml
\grep -lrE --include="*.xml" '<constant>[0-9]+<\/constant>' | xargs -d '\n' sed -i -E 's/<constant>([0-9]+)<\/constant>/<literal>\1<\/literal>/g'
\grep -lrE --include="*.xml" '<constant>[0-9]+\.[0-9]+<\/constant>' | xargs -d '\n' sed -i -E 's/<constant>([0-9]+\.[0-9]+)<\/constant>/<literal>\1<\/literal>/g'
\grep -lrE --include="*.xml" '<constant>[0-9]+.+<\/constant>' | xargs -d '\n' sed -i -E 's/<constant>([0-9]+.+)<\/constant>/<literal>\1<\/literal>/g'

[ndossche]

I believe this is right. Leaving open to see if other feedback comes in, and otherwise I'll merge.