standardized hero aura descriptions
This patch rephrases the aura descriptions of hero auras to an uniform standard, to ensure descriptions follow the actual modifications: [player] [class] [change] [attributes], e.g. "Spearmen +1 capture attack strength, +25% melee attack damage." instead of "+25% attack and +1 capture for spear soldiers."
The formation and garrison type aura descriptions are ugly; improvement suggestions are welcome.
Test Plan: Check for mistakes and omissions.
Reviewers: Gallaecio, Freagarach
Reviewed By: Gallaecio, Freagarach
Subscribers: Freagarach, elexis, Vulcan
Differential Revision: https://code.wildfiregames.com/D1808