always use line-wise C commentstring

[mortezadadgar]

separated this from the #84 as I think this require some discussions. this change has been made to follow default behavior of vim ftplugin which is always to use /* %s */ not matter it's block or line-wise commenting.
and besides that plugins like vim-commentray and mini.comment doesn't even support block commenting and therefore this come to surprising new users as their C commentstring has changed from this plugin

[JoosepAlviste]

This is an interesting case and I can see the reasoning of keeping the defaults from Vim. I also saw that support for single-line comments was added in C99, so it hasn't always been a part of the language.

However, this seems like a pretty subjective change and could be easily configured by the user. Also, this change would technically be a breaking change, so I'm quite hesitant to accept this.

Could we somehow ask for more opinions about this, from people who write C?

[mortezadadgar]

plugins like Comment.nvim already change the commentstring based on line or block wise mappings i don't see the rational of being in business of changing commentstring, after #86 get merged I don't think there's any reason to change commentstring where it's not needed, anything I am missing?