analyzer: Update comment_references rule for two-dotted names

Adds support for reporting `PropertyAccess`-resolved, two-dotted names
in comment references. Also big cleanup in the rule:

* Note that comment references are important for IDEs
* Change "in scope" to "in-scope"
* Give examples of each of the types of comment references (simple
  identifier, prefixed identifier, etc.)
* List the two-dotted name in the documentation
* Correct some grammar
* Add a doc comment to _Visitor.links, and rename to
  _Visitor.linkReferences

Cq-Include-Trybots: luci.dart.try:flutter-analyze-try,analyzer-win-release-try,pkg-win-release-try
Change-Id: I928894b07fc0e4d543b631dd17e4d6b69b5392e6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/373164
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Samuel Rawlins <srawlins@google.com>
Reviewed-by: Phil Quitslund <pquitslund@google.com>

https://dart.googlesource.com/sdk/+/f237ac80a48f6ebdbbd6d484fe99ac6ef4155fd0

DEPS

diff --git a/DEPS b/DEPS
index 3332f67..f277e07 100644
--- a/DEPS
+++ b/DEPS
@@ -282,7 +282,7 @@
 
   'engine/src/flutter': Var('flutter_git') + '/mirrors/engine' + '@' + '4a2ac0e51a8f0c80a37ed03c680785027e8435fb',
 
-  'engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + 'b99585d96997cc2dbfe2db34742993b880a869a4',
+  'engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + 'f237ac80a48f6ebdbbd6d484fe99ac6ef4155fd0',
 
   'flutter': Var('flutter_git') + '/mirrors/flutter' + '@' + '5ebc993dffe8ce7e91479b8ff7b003c1f464a621',
 

commits.json

diff --git a/commits.json b/commits.json
index 3c73a61..a824a3a 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
   "engine/src/flutter":"4a2ac0e51a8f0c80a37ed03c680785027e8435fb",
-  "engine/src/flutter/third_party/dart":"b99585d96997cc2dbfe2db34742993b880a869a4",
+  "engine/src/flutter/third_party/dart":"f237ac80a48f6ebdbbd6d484fe99ac6ef4155fd0",
   "flutter":"5ebc993dffe8ce7e91479b8ff7b003c1f464a621"
 }
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