Update es_ES.lang

In the spanish comunity we said "Slime" more frecuently.
Example:
"mobs.mobs5=Alpha 1.0.8
mobs.mobs5.desc=No hay slimes
mobs.slimes2.desc=Altura máx.: §r32§7, 10 veces más slimes
mobs.slimes3=Beta
mobs.slimes3.desc=Altura máx.: §r16§7, restricción de chunks
mobs.slimes4=1.0
mobs.slimes4.desc=Altura máx.: §r40§7, restricción de chunks
mobs.slimes5=1.3
mobs.slimes5.desc=Menos slimes en mundos superllanos
mobs.slimes6=1.4"

But

"mobs.slimes6.desc=Limos en pantanos
 mobs.slimes6=1.5
 mobs.slimes6.desc=Limos en pantanos dependiendo de la fase lunar"
Fixed.
Changed words and translations mistakes.
"nbxlite.biomelessfeatures4.desc=Cuevas y nueva generación" Will be this. If not, only change it :)

*In another pull I will fix more "1ra" or "3ra persona" and change it for the word. It's more understandable.