Replace "unpaired surrogates" with "isolated surrogate code units"

https://www.unicode.org/versions/Unicode17.0.0/core-spec/chapter-3/#G1654
https://www.unicode.org/charts/PDF/UDC00.pdf

src/java.base/share/classes/java/lang/CharSequence.java

@@ -255,7 +255,7 @@ public interface CharSequence {
 
     /**
      * {@return the number of Unicode code points in this character sequence}
-     * Unpaired surrogates count as one code point each.
+     * Isolated surrogate code units count as one code point each.
      *
      * @since 27
      */

src/java.base/share/classes/java/lang/Character.java

@@ -9979,7 +9979,7 @@ class Character implements java.io.Serializable, Comparable<Character>, Constabl
 
     /**
      * {@return the number of Unicode code points in the {@code char} array}
-     * Unpaired surrogates count as one code point each.
+     * Isolated surrogate code units count as one code point each.
      *
      * @param seq the {@code char} array
      * @throws NullPointerException if {@code seq} is null

src/java.base/share/classes/java/lang/String.java

@@ -1716,7 +1716,7 @@ public final class String
 
     /**
      * {@return the number of Unicode code points in this String}
-     * Unpaired surrogates count as one code point each.
+     * Isolated surrogate code units count as one code point each.
      *
      * @since 27
      */
@@ -1730,7 +1730,7 @@ public final class String
     /**
      * Returns the index within this {@code String} that is
      * offset from the given {@code index} by
-     * {@code codePointOffset} code points. Unpaired surrogates
+     * {@code codePointOffset} code points. Isolated surrogate code units
      * within the text range given by {@code index} and
      * {@code codePointOffset} count as one code point each.
      *