New merlin release changelog (#2740)

* New merlin release changelog

* rename file

* Formatting

* Update data/changelog/merlin/2024-09-27-merlin-5.2.1.md

Co-authored-by: Christine Rose <[email protected]>

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Co-authored-by: Christine Rose <[email protected]>

data/changelog/merlin/2024-09-27-merlin-5.2.1.md

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+---
+title: Merlin 5.2.1-502 for OCaml 5.2 and 4.17.1 for OCaml 5.1 and 4.14
+tags: [merlin, platform]
+changelog: |
+    + merlin binary
+        - A new WRAPPING_PREFIX configuration directive that can be used to tell Merlin what to append to the current unit name in the presence of wrapping (ocaml/merlin#1788)
+        - Add `-unboxed-types` and `-no-unboxed-types` as OCaml ignored flags (ocaml/merlin#1795, fixes ocaml/merlin#1794)
+        - Destruct: Refinement in the presence of optional arguments (ocaml/merlin#1800 ocaml/merlin#1807, fixes ocaml/merlin#1770)
+
+        - Implement new `expand-node` command for expanding PPX annotations (ocaml/merlin#1745)
+        - Implement new `inlay-hints` command for adding hints on a source tree (ocaml/merlin#1812)
+        - Implement new `search-by-type` command for searching values by types (ocaml/merlin#1828)
+        - Canonicalise paths in occurrences. This helps deduplicate the results and
+        - Show more user-friendly paths. (ocaml/merlin#1840)
+        - Fix `dot-merlin-reader` ignoring SOURCE_ROOT and STDLIB directives (ocaml/merlin#1839, ocaml/merlin#1803)
+    + editor modes
+        - Vim: 
+            - Fix Python-3.12 syntax warnings in `merlin.py` (ocaml/merlin#1798)
+            - Dead code / doc removal for previously deleted MerlinPhrase command (ocaml/merlin#1804)
+        - Emacs: 
+            - Improve the way that result of polarity search is displayed (#1814)
+            - Add `merlin-search-by-type`, `merlin-search-by-polarity` and change the behaviour of `merlin-search` to switch between by-type or by-polarity depending on the query (ocaml/merlin#1828)
+
+---
+
+We are happy to announce the joint release of Merlin `5.2.1-502` and `4.17.1`. This release adds many new features to Merlin including the ability to add hints to a source tree, serch for values using a type signature and expanding PPX annotations to preview their source code. There are also bug fixes for both the Merlin binary and editor modes. 
+
+More information can be found in the [Discuss announcement](https://discuss.ocaml.org/t/ann-new-release-of-merlin/15358).
+
+Contributions are always welcome at [Merlin | Issues](https://github.com/ocaml/merlin/issues)