Rework generation of government effects-driven help text, mainly to take
into account world bonuses and the resulting net effect value.
Fixes an issue where food Upkeep_Factor (for Settlers) was not reported
(Democracy/Republic in classic/civ2 ruleset), or even reported incorrectly
(Communism/Fundamentalism in civ2 ruleset).

See gna bug #20521.

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24263 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
A few textual changes to government help:
 * describe non-integer-ratio EFT_UPKEEP_FACTOR bonuses
 * better veteran description, including rank for unit type requirement
 * add missing PL_() i18n marking

See gna patch #4450.

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24264 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Add missing pluralisation i18n marking to a string about city population.

Noted by "Quintus" (Marvin Gülker).

See gna bug #21528.

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24265 a0f10bec-cc02-0410-94fc-a9cfff90b4cd