vim:plugs: Add vim-textobj-comment

> This Vim plugin provides text objects for comments.
>
> `ac` selects a comment including the comment delimiters and `ic`
> selects just the comment content. (There's also a third text object,
> `aC`, which selects a comment including trailing or leading
> whitespace.) These mappings are available in Visual and
> Operator-pending mode.
>
> This plugin uses the `comments` and `commentstring` settings to
> determine what a comment looks like for a given filetype. It works
> with both `/* paired */` and `// simple` comment delimiters.
>
> This plugin depends on the textobj-user plugin.

.gitmodules

@@ -77,6 +77,9 @@
 [submodule "vim-syntax-extra"]
 	path = .config/vim/pack/plugins/opt/vim-syntax-extra
 	url = https://github.com/justinmk/vim-syntax-extra
+[submodule "vim-textobj-comment"]
+	path = .config/vim/pack/plugins/opt/vim-textobj-comment
+	url = https://github.com/glts/vim-textobj-comment
 [submodule "vim-textobj-user"]
 	path = .config/vim/pack/plugins/opt/vim-textobj-user
 	url = https://github.com/kana/vim-textobj-user