Show WebView triggered by page_viewer in Active column

[renkun-ken]

Both viewer and page_viewer open WebView to show the resulted HTML file.

viewer is typically called by htmlwidgets to show a new page side-by-side with currently editing document while page_viewer (e.g. profvis) a new page in the current editor, which is consistent with RStudio behavior.

This PR distinguishes page_viewer and viewer by adding different viewColumn to the response they create and vscode-R handles them when updating response. Now, viewer uses viewColumn = "Two" while page_viewer uses viewColumn = "Active".

[andycraig]

@Ikuyadeu Can I suggest merging all of @renkun-ken's open PRs? I think it is okay not to test them, as currently these features are only visible to users who have enabled R: Session Watcher.

[Ikuyadeu]

@andycraig OK! Thank you for reviewing!

[andycraig]

@Ikuyadeu Can I merge all of @renkun-ken’s open PRs?

[renkun-ken]

It would be great if all my open PRs are merged since I'm constantly testing them in my work in my https://github.com/renkun-ken/vscode-R/tree/test branch which merges all my PRs whenever new commits are pushed to any of the PRs.

[Ikuyadeu]

@andycraig Yes! of course.

[andycraig]

@Ikuyadeu Great, thank you! I will merge them now.

@renkun-ken Sorry, I should have mentioned that I think they're safe to merge because I know you're testing them continuously at work. Merging them now. Thank you for all these improvements to vscode-R!

[Ikuyadeu]

@andycraig Thank you! I will publish a new version this weekend.