CHANGELOG.md: Add links to subsections in the USER_GUIDE.md

Author: bxparks

CHANGELOG.md

@@ -2,6 +2,11 @@
 
 * Unreleased
 * 2.1.0 (2023-01-29, TZDB version 2022g)
+    * There are a handful API breaking changes in this release in the pursuit of
+      simpler and cleaner code. See the following for more info:
+        * [Migrating to v2.1](MIGRATING.md#MigratingToVersion210)
+        * [ZonedExtra](USER_GUIDE.md#ZonedExtra) in the User Guide
+        * [Unified Links](USER_GUIDE.md#UnifiedLinks) in the User Guide
     * **Potentially Breaking**: zonedb,zonedbx
         * Rename `kPolicyXxx` to `kZonePolicyXxx` for consistency. These are
           expected to be used only internally, so shouldn't cause external
@@ -31,8 +36,6 @@
             * Removed `followLink` flag on various methods.
             * Only 2 methods apply to Links: `isLink()` and
               `printTargetNameTo()`.
-        * See [Migrating to v2.1](MIGRATING.md#MigratingToVersion210) for more
-          information.
     * Simplify ZoneProcessors
         * `ZoneProcessor.h`, `ExtendedZoneProcessor.h`, `BasicZoneProcessor.h`
         * Remove: `getUtcOffset()`, `getDeltaOffset()`, `getAbbrev()`
@@ -43,7 +46,7 @@
           `testing/tzonedb/` and `testing/tzonedbx/`.
             * Reduces maintenance cost of various hand-crafted ZoneInfo and
               ZonePolicy entries for unit tests.
-            * Can test against real timezones with predicatble behavior.
+            * Can test against real timezones with predictable behavior.
 * 2.0.1 (2022-12-04, TZDB 2022g)
     * Prevent `ExtendedZoneProcssor::generateStartUntilTimes()` from
       dereferencing uninitialized memory if there are no matching transitions.