Prevent null character in Windows home directory (#808) (#813)

Author: jrflat

Sources/FoundationEssentials/String/String+Path.swift

@@ -374,7 +374,7 @@ extension String {
                     guard GetEnvironmentVariableW(pwszVariable, $0.baseAddress, dwLength) == dwLength - 1 else {
                         return nil
                     }
-                    return String(decoding: $0, as: UTF16.self)
+                    return String(decodingCString: $0.baseAddress!, as: UTF16.self)
                 }
             }
         }
@@ -436,7 +436,7 @@ extension String {
             guard GetUserProfileDirectoryW(hToken, $0.baseAddress, &dwcchSize) else {
                 fatalError("unable to query user profile directory")
             }
-            return String(decoding: $0, as: UTF16.self)
+            return String(decodingCString: $0.baseAddress!, as: UTF16.self)
         }
 #else
         #if targetEnvironment(simulator)

Sources/FoundationEssentials/URL/URL.swift

@@ -1324,7 +1324,7 @@ public struct URL: Equatable, Sendable, Hashable {
         if result.count > 1 && result.utf8.last == UInt8(ascii: "/") {
             _ = result.popLast()
         }
-        let charsToLeaveEncoded = Set([UInt8(ascii: "/")])
+        let charsToLeaveEncoded: Set<UInt8> = [._slash, 0]
         return Parser.percentDecode(result, excluding: charsToLeaveEncoded) ?? ""
     }