docs: note rollup serializeTransform default

Author: Anber

.changeset/bump-wyw-1-0-x.md

@@ -18,5 +18,5 @@ This release updates Linaria's build-time evaluation engine (WyW). See https://w
 Notes:
 
 - If you import JSON from code that is evaluated by WyW, add `.json` to `extensions` and ensure `.json` is ignored by evaluation rules (so it's parsed as JSON, not by Babel).
-- Rollup users on WyW 1.0.6 may need to disable `serializeTransform` to avoid Rollup "Unexpected early exit" (see `examples/rollup/rollup.config.mjs`).
+- Rollup users: WyW 1.x serializes `transform()` by default (`serializeTransform: true`). If you hit Rollup "Unexpected early exit" (unresolved plugin promises / deadlock during resolve), set `serializeTransform: false` (see `examples/rollup/rollup.config.mjs`).
 - WyW 1.x promotes fully-statically-evaluatable modules to `only: ['*']` and can re-evaluate modules when cached exports are incomplete (cached export values might not be reused).

docs/MIGRATION_GUIDE.md

@@ -9,7 +9,7 @@ Linaria 7 updates the WyW toolchain (`@wyw-in-js/*`) to `^1.0.0` (stable). This
 - Review https://wyw-in-js.dev/stability for the evaluation model, common pitfalls, and performance guidance.
 - If you rely on WyW cache internals, note that WyW 1.x can promote fully-statically-evaluatable modules to `only: ['*']` and may re-evaluate modules when cached exports are incomplete.
 - If you import JSON from code that is evaluated by WyW, add `.json` to `extensions` and ensure `.json` is ignored by evaluation rules (so it's parsed as JSON, not by Babel).
-- Rollup users on WyW 1.0.6: if you hit Rollup "Unexpected early exit" (unresolved plugin promises), try `serializeTransform: false` in the WyW Rollup plugin config.
+- Rollup users on WyW 1.0.6: WyW serializes `transform()` by default; if you hit Rollup "Unexpected early exit" (unresolved plugin promises), try `serializeTransform: false` in the WyW Rollup plugin config.
 
 # 6.x from 5.x, 4.x, 3.x