Improve the point-free section of the style guide
Improve the point-free section of the style guide

Distinguish declaring functions in the point-free style and using
a very similar technique to avoid parentheses (which isn't technically
point-free).

Signed-off-by: Petr Pudlak <9d19625f8ee825a2c398462ed335cbcf98f79c32@google.com>
Reviewed-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>

onponomarev/ganeti,dimara/ganeti,andir/ganeti,leshchevds/ganeti,apyrgio/ganeti,ganeti/ganeti,andir/ganeti,yiannist/ganeti,ganeti-github-testing/ganeti-test-1,bitemyapp/ganeti,dimara/ganeti,apyrgio/ganeti,grnet/snf-ganeti,leshchevds/ganeti,yiannist/ganeti,mbakke/ganeti,mbakke/ganeti,onponomarev/ganeti,ganeti-github-testing/ganeti-test-1,ganeti/ganeti,mbakke/ganeti,leshchevds/ganeti,andir/ganeti,bitemyapp/ganeti,grnet/snf-ganeti,yiannist/ganeti,ganeti/ganeti