Migrate to 2021.3 Platform

Hi, in scope of https://youtrack.jetbrains.com/issue/IDEA-277609 the documentation subsystem was rewritten. The new implementation is enabled by default via documentation.v2 registry key.

The new implementation does not use com.intellij.codeInsight.documentation.DocumentationComponent and dependent APIs (which means com.intellij.codeInsight.documentation.DocumentationActionProvider is not used as well).

Please check out the new implementation in https://github.com/JetBrains/intellij-community/tree/master/platform/lang-impl/src/com/intellij/lang/documentation and tell me what APIs are required for your plugin, so I would have time to provide them for you before 2021.3 release.

[dovchinnikov]

Easily switch the display of the original documentation and the documentation after processing.

I’ve added com.intellij.lang.documentation.ide.DocumentationBrowserFacade and corresponding key com.intellij.lang.documentation.ide.actions.DOCUMENTATION_BROWSER to obtain it. See https://github.com/JetBrains/intellij-community/commit/b0dc835e699c151348fef9c4a69c6ccdb917e265 and https://github.com/JetBrains/intellij-community/commit/4d72e0c60953dd3c7ef6f5654be07ad4285ce059

With it the ToggleQuickDocTranslationAction could look like:

class ToggleQuickDocTranslationAction : ... {

    override fun update(e: AnActionEvent) {
        ...
        e.presentation.isEnabled = e.dataContext.getData(DOCUMENTATION_BROWSER) != null
    }

    override fun isSelected(e: AnActionEvent): Boolean {
        return Settings.translateDocumentation
    }

    override fun setSelected(e: AnActionEvent, state: Boolean) {
        Settings.translateDocumentation = state
        e.dataContext.getData(DOCUMENTATION_BROWSER)?.reload()
    }
}

[dovchinnikov]

Get the selection in the documentation.

This one is done by https://github.com/JetBrains/intellij-community/commit/899c6a834d0e0bba6f5852b6f720b7313f4cb024. It will be available in the EAP next week. The same com.intellij.codeInsight.documentation.DocumentationManager#SELECTED_QUICK_DOC_TEXT key works in the new implementation.