Wiki/Requirements: add more info about recommendations and links to other wiki docs

Author: jrfnl

wiki/Requirements.md

@@ -9,11 +9,11 @@ Additionally, PHP_CodeSniffer requires the following PHP extensions to be enable
 
 The following PHP extensions are not required, but are strongly recommended:
 - [DOM][dom]: used for displaying the sniff documentation via the `--generator=...` option.
-- [iconv]: used for accurate character length calculation in files containing multibyte characters. Without this extension, some sniffs, like `Generic.Files.LineLength`, may report incorrect results for lines containing non-ASCII characters, as PHP_CodeSniffer will fall back to byte-based length calculations.
-- [json]: required for the cache functionality, as well as for the JSON report output.
+- [iconv]: used for accurate character length calculation in files containing multibyte characters. Without this extension, some sniffs, like `Generic.Files.LineLength`, may report incorrect results for lines containing non-ASCII characters, as PHP_CodeSniffer will fall back to byte-based length calculations. Additionally, the following reports may not work correctly without this extension: [Checkstyle][wiki-report-checkstyle], [JUnit][wiki-report-junit] and [XML][wiki-report-xml].
+- [json]: required for the cache functionality, as well as for the [JSON report][wiki-report-json] output.
 - [PCNTL][pcntl]: required for parallel processing via the `--parallel` CLI option. Without this extension, PHP_CodeSniffer will not be able to check multiple files simultaneously.
 
-Individual sniffs may have additional requirements such as external applications and scripts. See the [Configuration Options](https://github.com/PHPCSStandards/PHP_CodeSniffer/wiki/Configuration-Options) manual page for a list of these requirements.
+Individual sniffs may have additional requirements such as external applications and scripts. See the [Configuration Options][wiki-config] manual page for a list of these requirements.
 
 > [!WARNING]
 > The [gRPC PHP extension][grpc] is known to cause PHP_CodeSniffer to hang when running with parallel processing enabled. If the gRPC extension is loaded, either do not use the `--parallel` CLI option or configure the extension's ini settings as follows:
@@ -30,3 +30,9 @@ Individual sniffs may have additional requirements such as external applications
 [simplexml]: https://www.php.net/book.simplexml
 [tokenizer]: https://www.php.net/book.tokenizer
 [xmlwriter]: https://www.php.net/book.xmlwriter
+
+[wiki-config]:            https://github.com/PHPCSStandards/PHP_CodeSniffer/wiki/Configuration-Options
+[wiki-report-checkstyle]: https://github.com/PHPCSStandards/PHP_CodeSniffer/wiki/Reporting#printing-a-checkstyle-report
+[wiki-report-json]:       https://github.com/PHPCSStandards/PHP_CodeSniffer/wiki/Reporting#printing-a-json-report
+[wiki-report-junit]:      https://github.com/PHPCSStandards/PHP_CodeSniffer/wiki/Reporting#printing-a-junit-report
+[wiki-report-xml]:        https://github.com/PHPCSStandards/PHP_CodeSniffer/wiki/Reporting#printing-an-xml-report