[deps] rev dartdoc, string_scanner, webdev

Revisions updated by `dart tools/rev_sdk_deps.dart`.

dartdoc (https://github.com/dart-lang/dartdoc/compare/9ed196f..29a1bbf):
  29a1bbf8  2023-01-04  Sam Rawlins  Migrate documentation_comment_test to be reflective (#3288)

string_scanner (https://github.com/dart-lang/string_scanner/compare/6ddab2c..c58618d):
  c58618d  2023-01-06  dependabot[bot]  Bump actions/checkout from 3.2.0 to 3.3.0 (#52)

webdev (https://github.com/dart-lang/webdev/compare/8795ca5..49f97b8):
  49f97b8  2023-01-06  Parker Lougheed  Replace deprecated implicit-casts option with strict-casts option (#1863)
  940c0ee  2023-01-06  Elliott Brooks (she/her)  Set a debug key for the injected client and Dart Debug Extension SSE clients (#1872)
  ae3e2ea  2023-01-06  Elliott Brooks (she/her)  [MV3] Dart Debug Extension supports cross-extension communication with AngularDart DevTools  (#1866)
  0662af9  2023-01-06  Anna Gringauze  Fix error message on dds failure2 (#1865)
  4f62035  2023-01-06  Elliott Brooks (she/her)  Can launch embedded Dart Debugger & Flutter Inspector (#1829)
  36fa973  2023-01-05  Elliott Brooks (she/her)  Refactor `TestContext` constructor for clarity (#1844)
  57776a0  2023-01-04  Elliott Brooks (she/her)  Use latest version of `package:sse` in the MV3 Debug Extension (#1859)

Change-Id: Ib97239b4f453238572dcccb9a0f81e4f1e969a04
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/278683
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
Auto-Submit: Devon Carew <devoncarew@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>

DEPS

@@ -125,7 +125,7 @@ vars = {
   # For more details, see https://github.com/dart-lang/sdk/issues/30164.
   "dart_style_rev": "d0c6b1da52c9f80679a7aaa05e5935ef5c6bb52f", # manually rev'd
 
-  "dartdoc_rev": "9ed196f1cec6c764c22acaa6599de5c30e361d4a",
+  "dartdoc_rev": "29a1bbf8576f39c6f7c7dcf71f131a59bb346625",
   "devtools_rev": "dd3fade2bd2ef74fc6102e56333a48f0efc594d3",
   "ffi_rev": "2a56c2a9a87122c057168874bde384debbb806b0",
   "file_rev": "b768f79dcd104a5feabafab47101c4355b71cd8f",
@@ -162,7 +162,7 @@ vars = {
   "sse_rev": "3c37edbd3fc0eced79abd26d78ec7d350340523a",
   "stack_trace_rev": "c08ee90b83380381a893d1e77a9a533d632f40e0",
   "stream_channel_rev": "0a7800ae41be5f7ba9990388fecc30a700186a48",
-  "string_scanner_rev": "6ddab2c6a3374c9b0fe5ba08ff9badce944a797e",
+  "string_scanner_rev": "c58618df0f17cbed664b3868c949abb13491e4d3",
   "sync_http_rev": "86226142aed0899792b7a0fa1ec491e03425aba3",
   "term_glyph_rev": "2bf45943466a5bb2d8d1add714fbfeebe5cabab5",
   "test_descriptor_rev": "b73c691c4e38e23bf8383148d3d68fa65e4a57e9",
@@ -176,7 +176,7 @@ vars = {
   "web_components_rev": "8f57dac273412a7172c8ade6f361b407e2e4ed02",
   "web_socket_channel_rev": "ebd0fe9ba8cbbb6f3d16b95092232a60dd867c5b",
   "WebCore_rev": "bcb10901266c884e7b3740abc597ab95373ab55c",
-  "webdev_rev": "8795ca5b89df0f912e31b0f5fa372b90f2a0bf66",
+  "webdev_rev": "49f97b8848c264e634affb045cf95ff4a34a7784",
   "webdriver_rev": "fcce0f0d0ebbda36398e1a6e3f29dfeb4eda43db",
   "webkit_inspection_protocol_rev": "ddb624cd85954dd384056cc253a8fc2b9da5364d",
   "yaml_edit_rev": "299f74594ff9fda412c1da5c0b5d5231d0c6fc42",