net: update quotation marks in comment

This change updates the use of quotation marks by replacing `ones' with 'ones'.
Quotation like `this' should not be used any more according to
https://www.cl.cam.ac.uk/~mgk25/ucs/quotes.html

Change-Id: I58470cdcc207864fbc8ca68ec0e77329bd81dc19
GitHub-Last-Rev: d03c81ebfba19a98a8dcc99451db60d129b43784
GitHub-Pull-Request: golang/go#33719
Reviewed-on: https://go-review.googlesource.com/c/go/+/190817Reviewed-by: Andrew Bonventre <andybons@golang.org>

src/net/ip.go

@@ -65,8 +65,8 @@ func IPv4Mask(a, b, c, d byte) IPMask {
 	return p
 }
 
-// CIDRMask returns an IPMask consisting of `ones' 1 bits
-// followed by 0s up to a total length of `bits' bits.
+// CIDRMask returns an IPMask consisting of 'ones' 1 bits
+// followed by 0s up to a total length of 'bits' bits.
 // For a mask of this form, CIDRMask is the inverse of IPMask.Size.
 func CIDRMask(ones, bits int) IPMask {
 	if bits != 8*IPv4len && bits != 8*IPv6len {