I wanted to keep the CSS class "button" for our green buttons and I
factorized this into local.css in 09b1cafd.

We should get rid of '<span class="button"> anyway as per #16221, but it
was much more simple to replace them by "bold" using sed commands
without breaking translations than to replace them with <strong>.

These strings were not translated

Currently translated at 71.4% (10 of 14 strings)

Translation: Tails/wiki/src/upgrade/linux.*.po
Translate-URL: https://translate.tails.boum.org/projects/tails/wikisrcupgradelinuxpo/ru/

Currently translated at 50.0% (2 of 4 strings)

Translation: Tails/wiki/src/upgrade/linux-overview.*.po
Translate-URL: https://translate.tails.boum.org/projects/tails/wikisrcupgradelinux-overviewpo/ru/

Currently translated at 88.8% (8 of 9 strings)

Translation: Tails/wiki/src/upgrade/linux-download.*.po
Translate-URL: https://translate.tails.boum.org/projects/tails/wikisrcupgradelinux-downloadpo/ru/

Currently translated at 60.0% (3 of 5 strings)