Pushing towards named placeholder in messages

[timofei-iatsenko]

Lingui supports deriving name of the placeholder from the variable name. It might sounds like a cool idea at the first glance, but that has few unexpected consequences.

Developers used to the fact that variable name doesn't affect how code is working. So renaming a variable should not break anything.

When a placeholder name is inherited from a variable name - it's breaking this rule, and developer could accidentaly rename variable and it would break the translation unexpectedly.

Also this inheritance will not work in the full-runtime macro which i'm having plans of implementing.

So i want to push thru the documentation and eslint rule to use a named placeholders evereywhere, and deprecate the old way.

ToDo List:

• Labeled placeholders implementation feat: add ph() and explicit labels for placeholders #2092
• Initial support of labeled placeholder ins the no-expression-in-message rule feat(no-expression-in-message): add support for ph and explicit labels eslint-plugin#100
• Support labeled placeholders in SWC plugin feat: support ph and explicit labels in t and Trans swc-plugin#139
• Add suggestion to the error message of no-expression-in-message to use a labeled placeholder
• Add autofix suggestion for the no-expression-in-message converting to labeled placeholder
• Write a separate guide for using placeholders in the lingui's t and Trans
• Mention in Agent Skills
• Create a migration to fix the whole project at once (?? TBD)