Improve snapshot tests

It is better to write paths than printing them, because
printing will escape them, and then it is hard to
transform the path.

[ci skip]

tests/testthat/_snaps/scan-deps.md

@@ -1,13 +1,13 @@
 # get_deps_cache_path
 
     Code
-      get_deps_cache_path()
+      writeLines(get_deps_cache_path())
     Output
-      [1] "<tempdir>/<tempfile>/R/pkgcache/deps/1"
+      <tempdir>/<tempfile>/R/pkgcache/deps/1
     Code
-      get_deps_cache_path("badcafe")
+      writeLines(get_deps_cache_path("badcafe"))
     Output
-      [1] "<tempdir>/<tempfile>/R/pkgcache/deps/1/ba/badcafe"
+      <tempdir>/<tempfile>/R/pkgcache/deps/1/ba/badcafe
 
 # clear_deps_cache
 

tests/testthat/test-scan-deps.R

@@ -18,8 +18,8 @@ test_that("get_deps_cache_path", {
   on.exit(unlink(tmp), add = TRUE)
 
   expect_snapshot(transform = transform_tempdir, {
-    get_deps_cache_path()
-    get_deps_cache_path("badcafe")
+    writeLines(get_deps_cache_path())
+    writeLines(get_deps_cache_path("badcafe"))
   })
 })