[Unknown Mod][Adventure map] Indicate the hero's level in the description text in the hero level up window

[LeHerosInconnu]

Indicate the hero's level in the description text in the hero level up window.

In the example, display:

"Mandigal has gained a level and is now at level 10."

Instead of:

"Mandigal has gained a level."

In fheroes2:

Related issue: #1390.

This is not an option.
This can be implemented directly in fheroes2.