docs(tvix/eval): fix some broken docstr references

There's some more left, but they've been renamed/refactored out of
sight.

Change-Id: I41579dedc74342b4c5f8cb39d2995b5b0c90b0f4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9372
Tested-by: BuildkiteCI
Reviewed-by: Connor Brewster <cbrewster@hey.com>
Autosubmit: flokli <flokli@flokli.de>

tvix/eval/src/compiler/mod.rs

@@ -350,7 +350,7 @@ impl Compiler<'_> {
     /// warnings in that expression.
     ///
     /// A warning about the that code being dead is assumed to already be
-    /// emitted by the caller of [compile_dead_code].
+    /// emitted by the caller of this.
     fn compile_dead_code(&mut self, slot: LocalIdx, node: ast::Expr) {
         self.dead_scope += 1;
         self.compile(slot, node);