'J' when joining two comment lines does not strip the leading comment indicator

[lopopolo]

Describe the bug
When executing J in normal mode to join lines, vim strips leading comment indicators if we are joining a comment line to another comment line.

To Reproduce
Steps to reproduce the behavior:

Execute normal J on any of the following lines in a TOML file. The # should be stripped when joining.

# XXX: load-bearing unused dependency.
#
# `rustyline` improperly declares its minimum version on `log` as `0.4` despite
# requiring `>=0.4.5` to compile. Link in at least the minimum version here so
# cargo pulls in at least 0.4.5, e.g. when using `-Zminimal-versions`.
#
# Upstream has not been willing to merge a patch to fix this, so hack around it
# here.
#
# See: https://github.com/kkawakam/rustyline/pull/583

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
If applicable, add screenshots to help explain your problem.
If remapping-related, please attach log output: https://github.com/VSCodeVim/Vim#debugging-remappings.

neovim behavior:

Screen.Recording.2024-12-30.at.8.24.37.PM.mov

VSCodeVim behavior:

Screen.Recording.2024-12-30.at.8.25.12.PM.mov

Environment (please complete the following information):

• Extension (VsCodeVim) version: 1.29.0
• VSCode version: 1.96.2
• OS: macOS Sequoia 15.2

Additional context
Add any other context about the problem here.

[simonsj]

I think this is a duplicate of #1352 which would require formatoptions + j -- formatoptions tracked in #5610.