documentation: improve breaking change documentation

reserve/CHANGELOG.md

@@ -22,10 +22,10 @@
 ||⚠️BREAKING CHANGE: `Response`' `statusCode` is defaulted to `200`|
 ||⚠️BREAKING CHANGE: Headers of mocked Request and Response returns strings or array of strings|
 ||⚠️BREAKING CHANGE: Mocked Request normalizes the received URL|
-||⚠️BREAKING CHANGE: `body` helper leverages request headers and offers conversion interface|
+||⚠️BREAKING CHANGE: `body` helper leverages request headers to switch between text and json deserialization|
 ||⚠️BREAKING CHANGE: `server-created` event is now renamed to `created`|
 ||⚠️BREAKING CHANGE: `match` interpretation and interpolation has evolved|
-||⚠️BREAKING CHANGE: `if-match` signature change|
+||⚠️BREAKING CHANGE: `if-match` signature and behavior change|
 ||Fix `use` to handle middleware that are not calling next|
 ||Response status code is preserved when set before `file`|
 ||`static` option for performant `file` delivery ([`doc`](file.md))|