update Opera installation note at https://adblockplus.org/en/development-builds

[philll]

Background

Replace this text with your reasoning that lead to wanting the change.
The Opera installation note at ​https://adblockplus.org/en/development-builds#installation is outdated and does not apply any longer, as it states that Opera only installes non-webstore extensions by dropping the file into the extensions settings page, which is not true: Opera adds the extension directly but requires the user to enable it manually.

What to change

At ​https://adblockplus.org/en/development-builds, replace the text

Opera doesn't allow extension installation from third-party sites. You have to download the development build and then drag the file into Opera's extensions page.

with this one:

Opera adds extensions not downloaded via the webstore but deactivates them by default. After adding the ABP development build, go to the extensions menu and enable it.