Refresh nightly trybuild UI snapshots to unblock Coverage workflow

[Copilot]

The Coverage GitHub Actions job was failing in pastey-test-suite UI compile-fail tests due to nightly rustc diagnostic output drift, not macro behavior regressions. This updates expected snapshots so CI compares against current compiler output.

• What changed

  • Updated 8 trybuild snapshot files under pastey-test-suite/tests/ui/*.stderr to match current nightly diagnostics.
  • Changes are snapshot-only (line context/note formatting differences), with no runtime or macro logic modifications.

• Affected snapshots

  • case-warning.stderr
  • extra-token-in-replace.stderr
  • invalid-replace-format.stderr
  • invalid-replace.stderr
  • multi-token-replace-arg.stderr
  • nested-group-single-token.stderr
  • no-value-before-replace.stderr
  • raw-mode-wrong-position.stderr

• Representative diff shape

    error: expected `)`
      --> tests/ui/extra-token-in-replace.rs:6:45
       |
  + 3 | macro_rules! m {
  +...
      6 |             struct [< $name:replace("a", "b", "c") >];
       |                                             ^
  ...
     11 | m!(Pastey);
       | ---------- in this macro invocation
  -    = note: this error originates in the macro `m` (...)