util: Update description files

- Spelling fix
- Add languages
- Update formatting
- Move notes that shouldn't be in the description file to a README

Change-Id: I4af37327d5834f8546a3f967585658fb5686f17a
Signed-off-by: Martin Roth <gaumless@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64581
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <felixsinger@posteo.net>
Reviewed-by: Maxim Polyakov <max.senia.poliak@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>

util/crossgcc/description.md

@@ -1 +1 @@
-A cross toolchain builder for -elf toolchains (ie. no libc support)
+A cross toolchain builder for -elf toolchains (ie. no libc support) `Bash`