[stdlib] make annotation adjustments

Author: glessard

stdlib/public/core/StringGuts.swift

@@ -17,6 +17,7 @@ import SwiftShims
 // functionality and guidance for efficiently working with Strings.
 //
 @frozen
+@_addressableForDependencies
 public // SPI(corelibs-foundation)
 struct _StringGuts: @unchecked Sendable {
   @usableFromInline

stdlib/public/core/StringUTF8View.swift

@@ -89,7 +89,6 @@ extension String {
   ///     print(String(s1.utf8.prefix(15))!)
   ///     // Prints "They call me 'B"
   @frozen
-  @_addressableForDependencies
   public struct UTF8View: Sendable {
     @usableFromInline
     internal var _guts: _StringGuts

stdlib/public/core/Substring.swift

@@ -630,7 +630,6 @@ extension Substring: LosslessStringConvertible {
 
 extension Substring {
   @frozen
-  @_addressableForDependencies
   public struct UTF8View: Sendable {
     @usableFromInline
     internal var _slice: Slice<String.UTF8View>