Fix #76260 Add nullable annotation to INumberBase<>.TryParse (#76304)

Co-authored-by: Michał Bryłka <michal.brylka@gmail.com>

Author: github-actions[bot]

src/libraries/System.Private.CoreLib/src/System/Numerics/INumberBase.cs

@@ -337,7 +337,7 @@ protected static abstract bool TryConvertToTruncating<TOther>(TSelf value, [Mayb
         /// <param name="result">On return, contains the result of successfully parsing <paramref name="s" /> or an undefined value on failure.</param>
         /// <returns><c>true</c> if <paramref name="s" /> was successfully parsed; otherwise, <c>false</c>.</returns>
         /// <exception cref="ArgumentException"><paramref name="style" /> is not a supported <see cref="NumberStyles" /> value.</exception>
-        static abstract bool TryParse([NotNullWhen(true)] string? s, NumberStyles style, IFormatProvider? provider, out TSelf result);
+        static abstract bool TryParse([NotNullWhen(true)] string? s, NumberStyles style, IFormatProvider? provider, [MaybeNullWhen(false)] out TSelf result);
 
         /// <summary>Tries to parses a span of characters into a value.</summary>
         /// <param name="s">The span of characters to parse.</param>
@@ -346,6 +346,6 @@ protected static abstract bool TryConvertToTruncating<TOther>(TSelf value, [Mayb
         /// <param name="result">On return, contains the result of successfully parsing <paramref name="s" /> or an undefined value on failure.</param>
         /// <returns><c>true</c> if <paramref name="s" /> was successfully parsed; otherwise, <c>false</c>.</returns>
         /// <exception cref="ArgumentException"><paramref name="style" /> is not a supported <see cref="NumberStyles" /> value.</exception>
-        static abstract bool TryParse(ReadOnlySpan<char> s, NumberStyles style, IFormatProvider? provider, out TSelf result);
+        static abstract bool TryParse(ReadOnlySpan<char> s, NumberStyles style, IFormatProvider? provider, [MaybeNullWhen(false)] out TSelf result);
     }
 }

src/libraries/System.Runtime/ref/System.Runtime.cs

@@ -10462,8 +10462,8 @@ protected static abstract bool TryConvertToTruncating<TOther>(TSelf value, [Syst
 #nullable disable
             where TOther : System.Numerics.INumberBase<TOther>;
 #nullable restore
-        static abstract bool TryParse(System.ReadOnlySpan<char> s, System.Globalization.NumberStyles style, System.IFormatProvider? provider, out TSelf result);
-        static abstract bool TryParse([System.Diagnostics.CodeAnalysis.NotNullWhenAttribute(true)] string? s, System.Globalization.NumberStyles style, System.IFormatProvider? provider, out TSelf result);
+        static abstract bool TryParse(System.ReadOnlySpan<char> s, System.Globalization.NumberStyles style, System.IFormatProvider? provider, [System.Diagnostics.CodeAnalysis.MaybeNullWhen(false)] out TSelf result);
+        static abstract bool TryParse([System.Diagnostics.CodeAnalysis.NotNullWhenAttribute(true)] string? s, System.Globalization.NumberStyles style, System.IFormatProvider? provider, [System.Diagnostics.CodeAnalysis.MaybeNullWhen(false)] out TSelf result);
     }
     public partial interface INumber<TSelf> : System.IComparable, System.IComparable<TSelf>, System.IEquatable<TSelf>, System.IFormattable, System.IParsable<TSelf>, System.ISpanFormattable, System.ISpanParsable<TSelf>, System.Numerics.IAdditionOperators<TSelf, TSelf, TSelf>, System.Numerics.IAdditiveIdentity<TSelf, TSelf>, System.Numerics.IComparisonOperators<TSelf, TSelf, bool>, System.Numerics.IDecrementOperators<TSelf>, System.Numerics.IDivisionOperators<TSelf, TSelf, TSelf>, System.Numerics.IEqualityOperators<TSelf, TSelf, bool>, System.Numerics.IIncrementOperators<TSelf>, System.Numerics.IModulusOperators<TSelf, TSelf, TSelf>, System.Numerics.IMultiplicativeIdentity<TSelf, TSelf>, System.Numerics.IMultiplyOperators<TSelf, TSelf, TSelf>, System.Numerics.INumberBase<TSelf>, System.Numerics.ISubtractionOperators<TSelf, TSelf, TSelf>, System.Numerics.IUnaryNegationOperators<TSelf, TSelf>, System.Numerics.IUnaryPlusOperators<TSelf, TSelf> where TSelf : System.Numerics.INumber<TSelf>?
     {