Make `lift ref` work

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 74.19355% with 8 lines in your changes are missing coverage. Please review.

Project coverage is 78.26%. Comparing base (9c55c0b) to head (cae081d). Report is 2 commits behind head on main.

Files	Patch %	Lines
base/src/main/java/org/aya/unify/Unifier.java	40.00%	3 Missing :warning:
base/src/main/java/org/aya/tyck/ExprTycker.java	50.00%	0 Missing and 1 partial :warning:
base/src/main/java/org/aya/tyck/TyckState.java	50.00%	1 Missing :warning:
...c/main/java/org/aya/tyck/error/MetaVarProblem.java	66.66%	1 Missing :warning:
.../src/main/java/org/aya/cli/utils/LiterateData.java	66.66%	0 Missing and 1 partial :warning:
...c/main/java/org/aya/prettier/ConcretePrettier.java	50.00%	0 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1078 +/- ## ============================================ + Coverage 78.19% 78.26% +0.07% - Complexity 3130 3134 +4 ============================================ Files 290 290 Lines 9666 9672 +6 Branches 1124 1124 ============================================ + Hits 7558 7570 +12 + Misses 1475 1469 -6 Partials 633 633 ```

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