Use an internal slot that makes clear we're using significant digits

Author: jessealama

spec.emu

@@ -419,7 +419,7 @@ location: https://github.com/tc39/proposal-decimal/
           <li>is <dfn>%Decimal128Amount%</dfn>.</li>
           <li>is the initial value of the the *"Amount"* property of the Decimal128 object.</li>
           <li>creates and initializes a new Decimal128.Amount object when called as a constructor</li>
-          <li>may be used as the value of an *extends* clause of a class definition. Subclass constructors that intend to inherit the specified Decimal128.Amount behaviour must include a *super* call to the Decimal128.Amount constructor to create and initialize the subclass instance with the [[Decimal128AmountData]] and [[Decimal128AmountPrecision]] internal slots.</li>
+          <li>may be used as the value of an *extends* clause of a class definition. Subclass constructors that intend to inherit the specified Decimal128.Amount behaviour must include a *super* call to the Decimal128.Amount constructor to create and initialize the subclass instance with the [[Decimal128AmountData]] and [[Decimal128AmountSignificantDigits]] internal slots.</li>
         </ul>
         <emu-clause id="sec-the-decimal128-amount-constructor-value">
           <h1>Decimal128.Amount ( _s_, _precision_ )</h1>
@@ -432,9 +432,9 @@ location: https://github.com/tc39/proposal-decimal/
             1. If ℝ(_precision_) is not an integer, throw a *RangeError* exception.
             1. If ℝ(_precision_) > 34, throw a *RangeError* exception.
             1. Let _decimal_ be ? Construct(%Decimal128%, _s_).
-            1. Let _O_ be ? OrdinaryCreateFromConstructor(NewTarget, *"%Decimal128Amount.prototype%"*, « [[Decimal128AmountData]], [[Decimal128AmountPrecision]] »).
+            1. Let _O_ be ? OrdinaryCreateFromConstructor(NewTarget, *"%Decimal128Amount.prototype%"*, « [[Decimal128AmountData]], [[Decimal128AmountSignificantDigits]] »).
             1. Set _O_.[[Decimal128AmountData]] to _decimal_.[[Decimal128Data]].
-            1. Set _O_.[[Decimal128AmountPrecision]] to _precision_.
+            1. Set _O_.[[Decimal128AmountSignificantDigits]] to _precision_.
             1. Return _O_.
           </emu-alg>
         </emu-clause>
@@ -1160,18 +1160,18 @@ location: https://github.com/tc39/proposal-decimal/
     <emu-alg>
       1. Let _O_ be the *this* value.
       1. Perform ? RequireInternalSlot(_O_, [[Decimal128AmountData]]).
-      1. Perform ? RequireInternalSlot(_O_, [[Decimal128AmountPrecision]]).
+      1. Perform ? RequireInternalSlot(_O_, [[Decimal128AmountSignificantDigits]]).
       1. Perform ? RequireInternalSlot(_x_, [[Decimal128AmountData]]).
-      1. Perform ? RequireInternalSlot(_x_, [[Decimal128AmountPrecision]]).
+      1. Perform ? RequireInternalSlot(_x_, [[Decimal128AmountSignificantDigits]]).
       1. Let _d1_ be _O_.[[Decimal128AmountData]].
       1. Let _d2_ be _x_.[[Decimal128AmountData]].
       1. Assert: _d1_ is a finite Decimal128 value.
       1. Assert: _d2_ is a finite Decimal128 value.
       1. If _d1_ is either *+0*<sub>𝔻</sub> or *-0*<sub>𝔻</sub>, set _d1_ to 0.
       1. If _d2_ is either *+0*<sub>𝔻</sub> or *-0*<sub>𝔻</sub>, set _d2_ to 0.
       1. If _d1_ ≠ _d2_, return *false*.
-      1. Let _precision1_ be _O_.[[Decimal128AmountPrecision]].
-      1. Let _precision2_ be _x_.[[Decimal128AmountPrecision]].
+      1. Let _precision1_ be _O_.[[Decimal128AmountSignificantDigits]].
+      1. Let _precision2_ be _x_.[[Decimal128AmountSignificantDigits]].
       1. Assert: _precision1_ is a non-negative integer.
       1. Assert: _precision2_ is a non-negative integer.
       1. If _precision1_ = _precision2_, return *true*.