fix: resolve remaining xref label gaps in swap-active build

Three small additions clear the cross-reference warnings tied to
underscore-vs-dash label form mismatches and the vpp-config-hugepages
reference that previously needed system.md in the canary set.

- system.rst: add .. _vpp-config-hugepages: alongside the existing
  underscore label so memory.md references resolve regardless of
  whether system.md is swap-active.
- md-lcp.md: add (vpp_config_dataplane_lcp_ignore-kernel-routes)=
  alongside dash form (carries upstream from myst/current 079fa786).
- md-memory.md: add (vpp_config_dataplane_memory)= alongside dash
  form (also from myst/current 079fa786).

Local clean swap-build with 106 canaries:
  before: 305 warnings, 8 undefined-label entries in our scope
  after:  300 warnings, 0 undefined-label entries in our scope

Remaining undefined-label warnings (release-notes, prepare_commit)
are in documentation.rst and unrelated to the canary swap mechanism.

🤖 Generated by [robots](https://vyos.io)

0 files changed, 0 insertions, 0 deletions