profiles: Prefix comment with # in package.mask

This multi-line comment accidentally only has a # prefix on the first
line, which leads to this warning during the build:

   --- Invalid atom in /mnt/host/source/src/third_party/coreos-overlay/profiles/coreos/base/package.mask: mask a specific version in hope that the future update may be smaller,
   --- Invalid atom in /mnt/host/source/src/third_party/coreos-overlay/profiles/coreos/base/package.mask: who knows.

Add missing prefixes to lines 2 and 3.

Signed-off-by: Jeremi Piotrowski <jpiotrowski@microsoft.com>

Author: jepio

sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.mask

@@ -22,6 +22,6 @@
 >=sys-block/thin-provisioning-tools-1.0.14
 
 # Too large to fit into our /boot partition - the size grew by 3MB. We
-mask a specific version in hope that the future update may be smaller,
-who knows.
+# mask a specific version in hope that the future update may be smaller,
+# who knows.
 =sys-firmware/intel-microcode-20250512_p20250513