Fix CS0266 in GetUnitInfo<TQuantity,TUnit> typed overload

The Azure Pipelines build of #1657 (master) fails with:

  error CS0266: Cannot implicitly convert type 'UnitInfo<TUnit>' to
    'UnitInfo<TQuantity, TUnit>'

at:

  return quantity.QuantityInfo[quantity.Unit];

The receiver is statically IQuantity<TQuantity, TUnit>, whose
QuantityInfo getter is shadowed (`new`) to return the more specific
QuantityInfo<TQuantity, TUnit>. Roslyn's member lookup on hosted
images resolves the inherited IQuantity<TUnit>.QuantityInfo
(QuantityInfo<TUnit>) instead, so the indexer returns UnitInfo<TUnit>
and the conversion to UnitInfo<TQuantity, TUnit> fails.

The runtime value is always the more derived type, so cast through
QuantityInfo<TQuantity, TUnit> explicitly to surface the typed
indexer. No behavior change.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: angularsen

UnitsNet/Extensions/QuantityExtensions.cs

@@ -44,7 +44,10 @@ public static UnitInfo<TQuantity, TUnit> GetUnitInfo<TQuantity, TUnit>(this IQua
         where TQuantity : IQuantity<TQuantity, TUnit>
         where TUnit : struct, Enum
     {
-        return quantity.QuantityInfo[quantity.Unit];
+        // Azure CI build failed on binding QuantityInfo through IQuantity<TUnit>, so cast to expose the fully typed indexer.
+        // This is likely a .NET SDK version compatibility thing, did not bother looking closer at it.
+        var quantityInfo = (QuantityInfo<TQuantity, TUnit>)quantity.QuantityInfo;
+        return quantityInfo[quantity.Unit];
     }
 
     /// <inheritdoc cref="IQuantity.As(UnitKey)" />