doc(dev) Add precision to install gcc-c++ for Fedora

Replace yum with dnf
Fix markdown

doc/dev/setup_env_dev.md

@@ -23,7 +23,7 @@ cargo xtask build
 To develop on Duniter, there is currently the following requirement:
 
 - A computer with GNU/Linux or Mac as operating system
-- Build essential tools
+- Build essential tools: Amongs other: GCC C++
 - wget
 - git (apt-get install git)
 - Rust
@@ -48,7 +48,7 @@ echo 'export PATH="$HOME/.cargo/bin:$PATH"' >> .bashrc
 
 ### Build the project
 
-#### Clone the repository
+#### Clone the repository
 
 ```bash
 git clone https://git.duniter.org/nodes/typescript/duniter

doc/use/manual_compilation.md

@@ -61,8 +61,11 @@ Depend on your distribution:
     apt-get install build-essential cmake
 
 ##### Fedora
+```bash
+sudo dnf install gcc-c++
+```
 
-    yum groupinstall "Development Tools" "Development Libraries"
+    dnf groupinstall "Development Tools" "Development Libraries"
 
 TODO: If you know how to install build essential tools for other gnu/linux distributions or for mac, you can complete this documentation and submit a merge request.