[stdlib] define properties also for ~Escapable elements

These should be available for any type of element `Span` can have in the future, including non-escapable elements. Making this change now avoids future churn.

Addresses rdar://146130842

Author: glessard

stdlib/public/core/Span/Span.swift

@@ -373,7 +373,7 @@ extension Span where Element: BitwiseCopyable {
 }
 
 @available(SwiftStdlib 6.2, *)
-extension Span where Element: ~Copyable {
+extension Span where Element: ~Copyable & ~Escapable {
 
   /// The number of elements in the span.
   ///

test/abi/macOS/arm64/stdlib.swift

@@ -798,9 +798,9 @@ Added: _$ss4SpanVsRi_zRi0_zrlE6_countSivg
 Added: _$ss4SpanVsRi_zRi0_zrlE6_countSivpMV
 Added: _$ss4SpanVsRi_zRi0_zrlE8_pointerSVSgvg
 Added: _$ss4SpanVsRi_zRi0_zrlE8_pointerSVSgvpMV
-Added: _$ss4SpanVsRi_zrlE5countSivpMV
-Added: _$ss4SpanVsRi_zrlE7indicesSnySiGvpMV
-Added: _$ss4SpanVsRi_zrlE7isEmptySbvpMV
+Added: _$ss4SpanVsRi_zRi0_zrlE5countSivpMV
+Added: _$ss4SpanVsRi_zRi0_zrlE7indicesSnySiGvpMV
+Added: _$ss4SpanVsRi_zRi0_zrlE7isEmptySbvpMV
 Added: _$ss4SpanVss15BitwiseCopyableRzlE9uncheckedxSi_tcipMV
 Added: _$ss4SpanVss15BitwiseCopyableRzlEyxSicipMV
 Added: _$ss7RawSpanV11byteOffsetsSnySiGvpMV

test/abi/macOS/x86_64/stdlib.swift

@@ -799,9 +799,9 @@ Added: _$ss4SpanVsRi_zRi0_zrlE6_countSivg
 Added: _$ss4SpanVsRi_zRi0_zrlE6_countSivpMV
 Added: _$ss4SpanVsRi_zRi0_zrlE8_pointerSVSgvg
 Added: _$ss4SpanVsRi_zRi0_zrlE8_pointerSVSgvpMV
-Added: _$ss4SpanVsRi_zrlE5countSivpMV
-Added: _$ss4SpanVsRi_zrlE7indicesSnySiGvpMV
-Added: _$ss4SpanVsRi_zrlE7isEmptySbvpMV
+Added: _$ss4SpanVsRi_zRi0_zrlE5countSivpMV
+Added: _$ss4SpanVsRi_zRi0_zrlE7indicesSnySiGvpMV
+Added: _$ss4SpanVsRi_zRi0_zrlE7isEmptySbvpMV
 Added: _$ss4SpanVss15BitwiseCopyableRzlE9uncheckedxSi_tcipMV
 Added: _$ss4SpanVss15BitwiseCopyableRzlEyxSicipMV
 Added: _$ss7RawSpanV11byteOffsetsSnySiGvpMV