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Going for a highlighting simpler solution, I would use a Vim custom syntax highlighting rule so that, for example, text marked like this:

~~ text ~~

is displayed in a different color (eg. a darker text color if you have a dark background)

Going for a highlighting simpler solution, I would use a Vim custom syntax highlighting rule so that, for example, text marked like this:

~~ text ~~

is displayed in a different color (eg. a darker text color if you have a dark background, or as dark reversed colors). Which would be, in vimrc:

au BufRead,BufNewFile *.txt   syntax match StrikeoutMatch /\~\~.*\~\~/   
hi def  StrikeoutColor   ctermbg=darkblue ctermfg=black    guibg=darkblue guifg=blue
hi link StrikeoutMatch StrikeoutColor

(where the au command is used to apply the rule to filetype .txt files only)

(Until is) lacking a better stikeout solution, I would use a Vim custom syntax highlighting rule so that, for example, text marked like this:

~~ text ~~

is displayed in a different color (eg. a darker text color if you have a dark background)

Going for a highlighting simpler solution, I would use a Vim custom syntax highlighting rule so that, for example, text marked like this:

~~ text ~~

is displayed in a different color (eg. a darker text color if you have a dark background)

I would add a custom syntax highlighting rule so that, for example, text marked like this:
~~ text ~~
is displayed in a different color (eg. a darker text color if you have a dark background)

(Until is) lacking a better stikeout solution, I would use a Vim custom syntax highlighting rule so that, for example, text marked like this:

~~ text ~~

is displayed in a different color (eg. a darker text color if you have a dark background)