NEWS: Clarify that offline mode is experimental

NEWS.md

@@ -5,7 +5,7 @@
 ### New features
 - Thumbnails can be disabled ([#897](https://github.com/fossar/selfoss/pull/897))
 - Reddit spout replaced fragile imgur heuristics with previews provided by the JSON API ([#1033](https://github.com/fossar/selfoss/pull/1033))
-- Support for **using selfoss offline** was added. Note that this is only available in [secure contexts](https://developer.mozilla.org/en-US/docs/Web/Security/Secure_Contexts), that is, over HTTPS. ([#1014](https://github.com/fossar/selfoss/issues/1014))
+- Experimental support for **using selfoss offline** was added. Note that this is only available in [secure contexts](https://developer.mozilla.org/en-US/docs/Web/Security/Secure_Contexts), that is, over HTTPS. ([#1014](https://github.com/fossar/selfoss/issues/1014))
 - Long articles will no longer be arranged into columns, allowing for smoother reading experience ([#1081](https://github.com/fossar/selfoss/pull/1081))
 - Diaspora share button was added, you can enable it with `d`. ([#1121](https://github.com/fossar/selfoss/pull/1121))
 - “Copy to clipboard” share button was added, you can enable it with `c`. ([#1142](https://github.com/fossar/selfoss/pull/1142))