Fix PR number in changelog

Author: edoardopirovano

extensions/ql-vscode/CHANGELOG.md

@@ -7,7 +7,7 @@
 - Allow using raw LGTM project slugs for fetching LGTM databases. [#769](https://github.com/github/vscode-codeql/pull/769)
 - Better error messages when BQRS interpretation fails to produce SARIF. [#770](https://github.com/github/vscode-codeql/pull/770)
 - Implement sorting of the query history view by name, date, and results count. [#777](https://github.com/github/vscode-codeql/pull/777)
-- Add some snippets for commonly used QL statements. [#780](https://github.com/github/vscode-codeql/pull/780)
+- Add some snippets for commonly used QL statements. [#782](https://github.com/github/vscode-codeql/pull/782)
 
 ## 1.4.3 - 22 February 2021