docs: add a clear note that we do not strictly follow PSR/PER (#2394)

* docs: add a clear note that we do not strictly follow PSR/PER

Closes #2288

* docs: improve verbiage of standard adherence note

Suggestion comes from the code review, thank you!

Co-authored-by: Christian Zosel <christian@zosel.ch>

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Co-authored-by: Christian Zosel <christian@zosel.ch>

README.md

@@ -37,6 +37,10 @@ Prettier is an opinionated code formatter. It enforces a consistent style by par
 
 This plugin adds support for the PHP language to Prettier.
 
+> [!NOTE]
+>
+> This plugin uses PSR / PER as guidance when making formatting decisions, but does not aim to be fully PSR / PER compliant. The idea is to stay reasonably close to how Prettier for JS works.
+
 ### Can this be used in production?
 
 We're considering the plugin to be stable when pure PHP files are formatted. Formatting of files that contain mixed PHP and HTML is still considered unstable - please see [open issues with the tag "inline"](/~https://github.com/prettier/plugin-php/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc+label%3Ainline) for details.