doc: fix PR link in CHANGELOG

PR-URL: https://github.com/iojs/io.js/pull/1624
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

CHANGELOG.md

@@ -22,7 +22,7 @@ _Note: a new version of the 'url' module was reverted prior to release as it was
   - The prefix used before the version number on `npm version` is now configurable via `tag-version-prefix` (@kkragenbrink) [npm/npm#8014](https://github.com/npm/npm/issues/8014)
 * **os**: `os.tmpdir()` is now cross-platform consistent and will no longer returns a path with a trailling slash on any platform (Christian Tellnes) [#747](https://github.com/iojs/io.js/pull/747)
 * **process**:
-  - `process.nextTick()` performance has been improved by between 2-42% across the benchmark suite, notable because this is heavily used across core (Brian White) [#1548](https://github.com/iojs/io.js/pull/1548)
+  - `process.nextTick()` performance has been improved by between 2-42% across the benchmark suite, notable because this is heavily used across core (Brian White) [#1571](https://github.com/iojs/io.js/pull/1571)
   - New `process.geteuid()`, `process.seteuid(id)`, `process.getegid()` and `process.setegid(id)` methods allow you to get and set effective UID and GID of the process (Evan Lucas) [#1536](https://github.com/iojs/io.js/pull/1536)
 * **repl**:
   - REPL history can be persisted across sessions if the `NODE_REPL_HISTORY_FILE` environment variable is set to a user accessible file, `NODE_REPL_HISTORY_SIZE` can set the maximum history size and defaults to `1000` (Chris Dickinson) [#1513](https://github.com/iojs/io.js/pull/1513)