Add '--nofork' flag to vim example in Appendix C

The -f/--nofork flag is suggested to be used "... when Vim is executed by a
program that will wait for the edit session to finish...." However, this flag
is used when Vim has the GUI version, effectively no-op'ing when non-GUI Vim.
This mirrors the existing "--nofork" flag for the Windows `gvim` example.

Author: ed-flanagan

C-git-commands.asc

@@ -66,7 +66,7 @@ Accompanying the configuration instructions in <<ch01-getting-started#_editor>>,
 |Textmate |`git config --global core.editor "mate -w"`
 |Textpad (Windows 64-bit) |`git config --global core.editor "'C:\Program Files\TextPad 5\TextPad.exe' -m` (Also see note below)
 |UltraEdit (Windows 64-bit) | `git config --global core.editor Uedit32`
-|Vim |`git config --global core.editor "vim"`
+|Vim |`git config --global core.editor "vim --nofork"`
 |Visual Studio Code |`git config --global core.editor "code --wait"`
 |VSCodium (Free/Libre Open Source Software Binaries of VSCode) | `git config --global core.editor "codium --wait"`
 |WordPad |`git config --global core.editor '"C:\Program Files\Windows NT\Accessories\wordpad.exe"'"`