update changelog

changelog.md

@@ -4,6 +4,7 @@
 * `NEW` settings: `Lua.diagnostics.libraryFiles`, `Lua.diagnostics.ignoredFiles`
 * `CHG` hover: improve showing multi defines
 * `CHG` hint: `Lua.hint.paramName` now supports `Disable`, `Literal` and `All`
+* `CHG` completion: new setting `Lua.completion.showWord`
 * `CHG` no longer ignore file names case in Windows
 * `CHG` watching library changes
 * `FIX` runtime errors