docs: fix unpacking instructions
docs: fix unpacking instructions

File names were wrong, file formats were wrong, bunzip command was
wrong...

I also removed all but the simplest example; people who use pipes already
know how to untar, so let's simplify and remove potential confusion for
non-tech-savvy users.

Signed-off-by: Eric Engestrom <de0b63cf2dfb1fae8ed3c3b4244856a05677d4f0@imgtec.com>
Reviewed-by: Brian Paul <3cb4e1df5ec4da2c7c4af7c52cec8cf340a55a10@vmware.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler