doc: Fix instruction for Fedora 27 or newer

- Fixes rust-embedded#249 - Fedora has no packaged named
  "`arm-none-eabi-gdb`"
- In the **Rust Embedded Discovery** book, it is noted to use `gdb`
  instead of `arm-none-eabi-gdb` as pointed out in rust-embedded/discovery#364
  that `gdb` on Fedora justworks(tm). This was fixed for _Discovery_
  book via rust-embedded/discovery#376
- Likewise, as mentioned per my comment in rust-embedded#249, on
  Fedora 37, `gdb` justworks(tm) as well.

src/intro/install/linux.md

@@ -39,16 +39,13 @@ sudo apt install gdb-arm-none-eabi openocd qemu-system-arm
 
 - Fedora 27 or newer
 
-> **NOTE** `arm-none-eabi-gdb` is the GDB command you'll use to debug your ARM
-> Cortex-M programs
-
 <!-- Fedora 27 -->
 <!-- GDB 7.6 (!) -->
 <!-- OpenOCD 0.10.0 -->
 <!-- QEMU 2.10.2 -->
 
 ``` console
-sudo dnf install arm-none-eabi-gdb openocd qemu-system-arm
+sudo dnf install gdb openocd qemu-system-arm
 ```
 
 - Arch Linux