chore(RingTheory/Valuation): move ValuativeRel to ValuativeRel.Basic (#28890)

in preparation for trivial rel and discrete rel files

like in #27313

Co-authored-by: Yakov Pechersky <ffxen158@gmail.com>

Author: pechersky

Mathlib.lean

@@ -5786,6 +5786,7 @@ import Mathlib.RingTheory.Valuation.ValExtension
 import Mathlib.RingTheory.Valuation.ValuationRing
 import Mathlib.RingTheory.Valuation.ValuationSubring
 import Mathlib.RingTheory.Valuation.ValuativeRel
+import Mathlib.RingTheory.Valuation.ValuativeRel.Basic
 import Mathlib.RingTheory.WittVector.Basic
 import Mathlib.RingTheory.WittVector.Compare
 import Mathlib.RingTheory.WittVector.Complete

Mathlib/RingTheory/Valuation/RankOne.lean

@@ -7,7 +7,7 @@ import Mathlib.Algebra.Order.Group.Units
 import Mathlib.Algebra.Order.GroupWithZero.WithZero
 import Mathlib.Analysis.SpecialFunctions.Pow.Real
 import Mathlib.Data.Real.Embedding
-import Mathlib.RingTheory.Valuation.ValuativeRel
+import Mathlib.RingTheory.Valuation.ValuativeRel.Basic
 
 /-!
 # Rank one valuations