Add version placeholders to the reporter docs

docs/command-line.md

@@ -125,6 +125,8 @@ Test names containing special characters, such as `,` or `[` can specify them on
 
 <pre>-r, --reporter &lt;reporter[::output-file]&gt;</pre>
 
+> Support for providing output-file through the `-r`, `--reporter` flag was [introduced](https://github.com/catchorg/Catch2/pull/2183) in Catch2 X.Y.Z
+
 A reporter is an object that formats and structures the output of running tests, and potentially summarises the results. By default a console reporter is used that writes, IDE friendly, textual output. Catch comes bundled with some alternative reporters, but more can be added in client code.<br />
 The bundled reporters are:
 

docs/reporters.md

@@ -38,6 +38,8 @@ By default all these reports are written to stdout, but can be redirected to a f
 <a id="multiple-reporters"></a>
 ## Using multiple reporters
 
+> Support for having multiple parallel reporters was [introduced](https://github.com/catchorg/Catch2/pull/2183) in Catch2 X.Y.Z
+
 Multiple reporters may be used at the same time, e.g. to save a machine-readable output to a file but still print the human-readable output to the console:
 ```
 -r console -r xml::result.xml -r junit::result-junit.xml