chore(Order/Defs/PartialOrder): fix naming of DecidableLE' (#31816)

The rename `DecidableGE` -> `DecidableLE'` wasn't done everywhere, and this PR fixes that.

Author: JovanGerb

Mathlib/Order/Defs/PartialOrder.lean

@@ -147,7 +147,7 @@ instance instTransGTGE : @Trans α α α GT.gt GE.ge GT.gt := ⟨lt_of_lt_of_le'
 instance instTransGEGT : @Trans α α α GE.ge GT.gt GT.gt := ⟨lt_of_le_of_lt'⟩
 
 /-- `<` is decidable if `≤` is. -/
-@[to_dual decidableGTOfDecidableGE /-- `<` is decidable if `≤` is. -/]
+@[to_dual decidableLT'OfDecidableLE' /-- `<` is decidable if `≤` is. -/]
 def decidableLTOfDecidableLE [DecidableLE α] : DecidableLT α :=
   fun _ _ => decidable_of_iff _ lt_iff_le_not_ge.symm
 
@@ -206,7 +206,7 @@ lemma lt_of_le_of_ne : a ≤ b → a ≠ b → a < b := fun h₁ h₂ =>
   lt_of_le_not_ge h₁ <| mt (le_antisymm h₁) h₂
 
 /-- Equality is decidable if `≤` is. -/
-@[to_dual decidableEqofDecidableGE /-- Equality is decidable if `≤` is. -/]
+@[to_dual decidableEqofDecidableLE' /-- Equality is decidable if `≤` is. -/]
 def decidableEqOfDecidableLE [DecidableLE α] : DecidableEq α
   | a, b =>
     if hab : a ≤ b then