Update CHANGELOG.md for 2.15.3

CHANGELOG.md

@@ -16,6 +16,54 @@
      checklist for a CLI release, you can edit here. But then
      you know what to do).
 -->
+## Release 2.15.3 (2023-11-22)
+
+### New features
+
+- A new compilation flag (`--fail-on-ambiguous-relation-name`) has been added to specify
+  that compilation should fail if the compiler generates an ambiguous relation name.
+- The new (advanced) command-line option `--[no-]linkage-aware-import` disables the
+  linkage-awareness phase of `codeql dataset import`, as a quick fix (at the expense of
+  database completeness) for C++ projects where this part of database creation consumes
+  too much memory. This option is available in the commands `database create`,
+  `database finalize`, `database import`, `dataset import`, `test extract`, and
+  `test run`.
+- The CodeQL language server now provides basic support for Rename, and you can
+  now use the Rename Symbol functionality in Visual Studio Code for CodeQL. The
+  current Rename support is less a refactoring tool and more a labor-saving
+  device. You may have to perform some manual edits after using Rename, but it
+  should still be faster and less work than renaming a symbol manually.
+- `codeql database analyze` now defaults to include markdown query help for all custom
+  queries with help files available. To change the default behaviour you can pass the
+  new flag `--sarif-include-query-help`, which provides the options `always` (which
+  includes query help for all queries), `custom_queries_only` (the default) and `never`
+  (which does not include query help for any query). The existing flag
+  `--sarif-add-query-help` has been deprecated and will be removed in a future release.
+
+### Improvements
+
+- The Find References feature in the CodeQL language server now supports all
+  CodeQL identifiers and offers improved performance compared to CodeQL CLI
+  2.14 releases.
+- The compiler generates shorter human-readable DIL and RA relation names. Due
+  to use of an extended character set, full VS Code support for short relation
+  names requires VS Code extension 1.9.4 or newer. 
+- `codeql database create` and `codeql database finalize` now log more diagnostic
+  information during database finalization, including the size of each relation, their
+  total size, and the rate at which they were written to disk.
+
+### Bugs fixed
+
+- Fixed an internal error in the compiler when arguments to the `codePointCount` string
+  primitive were not bound.
+- Fixed a bug where `codeql database finalize` would fail if a
+  database under construction was moved between machines between
+  `codeql database init` and `codeql database finalize`.  This should
+  now work, as long as both commands are run by the same _release_ of
+  the CodeQL CLI and the extractors used are the ones bundled with the
+  CLI.
+- Fixed a bug where `codeql database run-queries` would fail in some
+  circumstances when the database path included an `@`.
 
 ## Release 2.15.2 (2023-11-13)
 
@@ -65,7 +113,7 @@
 
 ### Deprecations
 
-- The accepted values of the `codeql database cleanup --mode=` command line option have been renamed to bring them in line with what they are called in the VSCode extension and the query server:
+- The accepted values of the `--mode` option for `codeql database cleanup`  have been renamed to bring them in line with what they are called in the VSCode extension and the query server:
   - `--mode=brutal` is now `--mode=clear`.
   - `--mode=normal` is now `--mode=trim`.
   - `--mode=light` is now `--mode=fit`.
@@ -74,6 +122,9 @@
 ### Improvements
 
 - The list of failed tests at the end of a `codeql test run` is now sorted lexicographically.
+- The syntax of DIL now more closely resembles the QL source code that it is
+  compiled from. In particular, conjunctions and disjunctions now use the
+  familiar `and` and `or` keywords, and clauses are enclosed in curly braces.
 
 ### Bugs fixed