types/descriptorpb: regenerate using latest protobuf v29.1 release

This updates all generated code to match the contents of the latest
v29.1 release of Protobuf. The main significant change is that
SourceCodeInfo is now extendable (though in a very limited way).

This release of Protobuf includes new conformance tests that do not
pass with the latest version of this protobuf-go module. These have
been added to the list of known-failing tests. However all of them
are marked "required" in the conformance suite so should be likely
be addressed as soon as possible. (This change makes no attempt to
fix any of them.)

Change-Id: Ib554d393d7742b7a616af998eeab84a080a85e0e
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/634015
Reviewed-by: Chressie Himpel <chressie@google.com>
Reviewed-by: Michael Stapelberg <stapelberg@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

integration_test.go

@@ -33,7 +33,7 @@ var (
 	regenerate   = flag.Bool("regenerate", false, "regenerate files")
 	buildRelease = flag.Bool("buildRelease", false, "build release binaries")
 
-	protobufVersion = "27.0"
+	protobufVersion = "29.1"
 
 	golangVersions = func() []string {
 		// Version policy: oldest supported version of Go, plus the version before that.

internal/conformance/failing_tests_text_format.txt

@@ -8,3 +8,11 @@ Recommended.Proto3.TextFormatInput.StringLiteralShortUnicodeEscapeSurrogatePairB
 Recommended.Proto3.TextFormatInput.StringLiteralShortUnicodeEscapeSurrogatePairString                              # Should have failed to parse, but didn't.
 Recommended.Proto3.TextFormatInput.StringLiteralUnicodeEscapeSurrogatePairLongShortBytes                           # Should have failed to parse, but didn't.
 Recommended.Proto3.TextFormatInput.StringLiteralUnicodeEscapeSurrogatePairLongShortString                          # Should have failed to parse, but didn't.
+
+# Recently added test cases. Since these are marked "required", they should be fixed ASAP.
+Required.Editions_Proto2.TextFormatInput.ClosedEnumFieldWithUnknownNumber                                          # Should have failed to parse, but didn't.
+Required.Editions_Proto3.TextFormatInput.FloatFieldNoNegativeOctal                                                 # Should have failed to parse, but didn't.
+Required.Editions_Proto3.TextFormatInput.FloatFieldNoOctal                                                         # Should have failed to parse, but didn't.
+Required.Proto2.TextFormatInput.ClosedEnumFieldWithUnknownNumber                                                   # Should have failed to parse, but didn't.
+Required.Proto3.TextFormatInput.FloatFieldNoNegativeOctal                                                          # Should have failed to parse, but didn't.
+Required.Proto3.TextFormatInput.FloatFieldNoOctal                                                                  # Should have failed to parse, but didn't.