docs: rename twitter to X, fix link (ohmyzsh#12532)

README.md

@@ -486,4 +486,4 @@ Oh My Zsh is released under the [MIT license](LICENSE.txt).
 
 ![Planet Argon](https://pa-github-assets.s3.amazonaws.com/PARGON_logo_digital_COL-small.jpg)
 
-Oh My Zsh was started by the team at [Planet Argon](https://www.planetargon.com/?utm_source=github), a [Ruby on Rails development agency](http://www.planetargon.com/services/ruby-on-rails-development?utm_source=github). Check out our [other open source projects](https://www.planetargon.com/open-source?utm_source=github).
+Oh My Zsh was started by the team at [Planet Argon](https://www.planetargon.com/?utm_source=github), a [Ruby on Rails development agency](https://www.planetargon.com/services/ruby-on-rails-development?utm_source=github). Check out our [other open source projects](https://www.planetargon.com/open-source?utm_source=github).

tools/upgrade.sh

@@ -271,7 +271,7 @@ if LANG= git pull --quiet --rebase $remote $branch; then
     printf '%s    %s        %s           %s /____/ %s       %s     %s          %s\n'      $RAINBOW $RESET
     printf '\n'
     printf "${BLUE}%s${RESET}\n\n" "$message"
-    printf "${BLUE}${BOLD}%s %s${RESET}\n" "To keep up with the latest news and updates, follow us on Twitter:" "$(fmt_link @ohmyzsh https://twitter.com/ohmyzsh)"
+    printf "${BLUE}${BOLD}%s %s${RESET}\n" "To keep up with the latest news and updates, follow us on X:" "$(fmt_link @ohmyzsh https://x.com/ohmyzsh)"
     printf "${BLUE}${BOLD}%s %s${RESET}\n" "Want to get involved in the community? Join our Discord:" "$(fmt_link "Discord server" https://discord.gg/ohmyzsh)"
     printf "${BLUE}${BOLD}%s %s${RESET}\n" "Get your Oh My Zsh swag at:" "$(fmt_link "Planet Argon Shop" https://shop.planetargon.com/collections/oh-my-zsh)"
   elif [[ $verbose_mode == minimal ]]; then