Bump dartdoc to ~5.1.0

Change-Id: Iee217a3cab8653828b7437cf89c68d31c41dd284
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/239241
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Samuel Rawlins <srawlins@google.com>

CHANGELOG.md

@@ -137,6 +137,17 @@ Updated the Linter to `1.22.0`, which includes changes that
 - updates `unnecessary_late` to report on variable names.
 - marks `null_check_on_nullable_type_parameter` stable.
 
+#### Dartdoc
+
+Updated dartdoc to 5.1.0, which includes changes that
+
+- support the enhanced enums feature
+- remove superfluous `[...]` links
+- fix `categoryOrder` option
+- display categorized extensions
+- add annotations to extensions
+- make minor improvements to performance
+
 ## 2.16.2 - 2022-03-24
 
 This is a patch release that fixes a dart2js crash when building some Flutter

DEPS

@@ -109,7 +109,7 @@ vars = {
   # For more details, see https://github.com/dart-lang/sdk/issues/30164
   "dart_style_rev": "d7b73536a8079331c888b7da539b80e6825270ea",
 
-  "dartdoc_rev" : "a39f378f8100b907e6285ac825967d764fd664ad",
+  "dartdoc_rev" : "334072b0cad436c05f6bcecf8a1a59f2f0809b84",
   "devtools_rev" : "65c40d3f6b3dd03411cb8f4b0c0b1ecaa9148f26",
   "ffi_rev": "4dd32429880a57b64edaf54c9d5af8a9fa9a4ffb",
   "fixnum_rev": "848341f061359ef7ddc0cad472c2ecbb036b28ac",