docs: drop breaking marker from pluggable HTTP client entry

The default impit-based behavior is unchanged and ApifyClient's
constructor signature is identical; the change is additive (new ABCs,
new with_custom_http_client classmethod, new top-level exports).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: vdusek

CHANGELOG.md

@@ -9,7 +9,7 @@ All notable changes to this project will be documented in this file.
 
 ### 🚀 Features
 
-- [**breaking**] Make HTTP client pluggable with abstract base classes ([#641](https://github.com/apify/apify-client-python/pull/641)) ([5ae33a0](https://github.com/apify/apify-client-python/commit/5ae33a0a801fdacd0c456a8630fea053f9df6550)) by [@vdusek](https://github.com/vdusek), closes [#416](https://github.com/apify/apify-client-python/issues/416)
+- Make HTTP client pluggable with abstract base classes ([#641](https://github.com/apify/apify-client-python/pull/641)) ([5ae33a0](https://github.com/apify/apify-client-python/commit/5ae33a0a801fdacd0c456a8630fea053f9df6550)) by [@vdusek](https://github.com/vdusek), closes [#416](https://github.com/apify/apify-client-python/issues/416)
 - [**breaking**] Introduce tiered timeout system with per-endpoint configuration ([#653](https://github.com/apify/apify-client-python/pull/653)) ([723ec6e](https://github.com/apify/apify-client-python/commit/723ec6e5954474767a5ecbf4902d9b62f7d214f8)) by [@vdusek](https://github.com/vdusek)
 - [**breaking**] Update default timeout tiers on non-storage resource clients ([#664](https://github.com/apify/apify-client-python/pull/664)) ([0b35bbe](https://github.com/apify/apify-client-python/commit/0b35bbe212a8a64c5aea5d5d813315252760b055)) by [@vdusek](https://github.com/vdusek)
 - Accept Pydantic models as alternatives to dicts in resource client methods ([#663](https://github.com/apify/apify-client-python/pull/663)) ([b778c20](https://github.com/apify/apify-client-python/commit/b778c2040228ff9f5a97765de10535cec3f0353e)) by [@vdusek](https://github.com/vdusek), closes [#421](https://github.com/apify/apify-client-python/issues/421)