Add build dependencies on Fedora Linux

Dependencies

• [2] LLS53CR2 Add installation instructions for openSUSE Tumbleweed
• [3] BRV6TU4B Turning the Installation page more beginner-friendly
• [4] SCSV2FNS Reboot

Change contents

• edit in src/installing.md at line 50
  [2.138]

  [3.1365]
  + **On Fedora Linux**

  + ```

  + sudo dnf install clang-devel openssl-devel libsodium-devel libzstd-devel pkgconfig xxhash-devel

  + ```

  +
• replacement in README.md at line 8
  [4.506173]→[4.506173:506228](∅→∅)
  − [mdbook](https://rust-lang-nursery.github.io/mdBook/).
  [4.506173]
  + [mdbook](https://rust-lang.github.io/mdBook/).