Add more examples

Author: Dave Bartolomeo

Adding change notes.md

@@ -3,7 +3,7 @@
 Each CodeQL query pack or library pack has its own change log to track how that pack changes with each release. Any non-trivial, user-visible change to a query or library should add a change note to the affected pack. This document describes how to do that.
 
 ## Creating a change note
-To create a new change note for a pack, create a new markdown file in the `change-notes` directory of the pack (e.g., in `cpp/ql/src/change-notes` for the C++ standard query pack). The markdown file must be named `YYYY-MM-DD-id.md`, where `YYYY-MM-DD` is the date of the change, and `id` is a short string to help identify the change. For example, if you were adding a new integer overflow query to the C++ standard query pack, you might do so from a branch named `int-overflow-query`, with a change note file named `cpp/ql/src/change-notes/2021-12-14-int-overflow-query.md`. Here is an example change note file:
+To create a new change note for a pack, create a new markdown file in the `change-notes` directory of the pack (e.g., in `cpp/ql/src/change-notes` for the C++ standard query pack). The markdown file must be named `YYYY-MM-DD-id.md`, where `YYYY-MM-DD` is the date of the change, and `id` is a short string to help identify the change. For example, if you were adding a new integer overflow query to the C++ standard query pack, you might do so from a branch named `int-overflow-query`, with a change note file named `cpp/ql/src/change-notes/2021-12-14-int-overflow-query.md`. Here are a few example change note files:
 
 ```yaml
 ---
@@ -12,6 +12,27 @@ category: newQuery
 * Added a new query, `cpp/integer-overflow`, to detect code that depends on the result of signed integer overflow.
 ```
 
+```yaml
+---
+category: fix
+---
+* Fixed a performance issue where the `cpp/integer-overflow` query would time out on large databases.
+```
+
+```yaml
+---
+category: minorAnalysis
+---
+* Added taint flow model for `std::codecvt`.
+```
+
+```yaml
+---
+category: majorAnalysis
+---
+* Added taint flow model for `std::string`.
+```
+
 ### Metadata
 The change note file requires some metadata at the beginning of the file. This metadata is later used to determine how to advance the version number of the pack next time it is published, and to group related change notes in the final changelog. The metadata is YAML, enclosed by a `---` line before and after.