maintner/maintnerd: improve API documentation

Rearrange the maintner API documentation, and reflect the guarantee of
at least two Go releases on success.

Updates golang/go#32606

Change-Id: I90d5017f280254cc6482e747ffc1534f8a51bc20
Reviewed-on: https://go-review.googlesource.com/c/build/+/182981
Run-TryBot: Alexander Rakoczy <alex@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
diff --git a/maintner/maintnerd/apipb/api.pb.go b/maintner/maintnerd/apipb/api.pb.go
index 7767d65..0ee86ad 100644
--- a/maintner/maintnerd/apipb/api.pb.go
+++ b/maintner/maintnerd/apipb/api.pb.go
@@ -273,8 +273,6 @@
 	return 0
 }
 
-// By default, ListGoReleases returns only the latest patches
-// of releases that are considered supported per policy.
 type ListGoReleasesRequest struct {
 }
 
@@ -284,7 +282,6 @@
 func (*ListGoReleasesRequest) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{8} }
 
 type ListGoReleasesResponse struct {
-	// Releases are Go releases, sorted by version with latest first.
 	Releases []*GoRelease `protobuf:"bytes,1,rep,name=releases" json:"releases,omitempty"`
 }
 
@@ -397,9 +394,16 @@
 	GetRef(ctx context.Context, in *GetRefRequest, opts ...grpc.CallOption) (*GetRefResponse, error)
 	// GoFindTryWork finds trybot work for the coordinator to build & test.
 	GoFindTryWork(ctx context.Context, in *GoFindTryWorkRequest, opts ...grpc.CallOption) (*GoFindTryWorkResponse, error)
-	// ListGoReleases lists Go releases. A release is considered to exist for
-	// each git tag named "goX", "goX.Y", or "goX.Y.Z", as long as it has a
-	// corresponding "release-branch.goX" or "release-branch.goX.Y" release branch.
+	// ListGoReleases lists Go releases sorted by version with latest first.
+	//
+	// A release is considered to exist for each git tag named "goX", "goX.Y", or
+	// "goX.Y.Z", as long as it has a corresponding "release-branch.goX" or
+	// "release-branch.goX.Y" release branch.
+	//
+	// ListGoReleases returns only the latest patch versions of releases which
+	// are considered supported per policy. For example, Go 1.12.6 and 1.11.11.
+	// The response is guaranteed to have two versions, otherwise an error
+	// is returned.
 	ListGoReleases(ctx context.Context, in *ListGoReleasesRequest, opts ...grpc.CallOption) (*ListGoReleasesResponse, error)
 }
 
@@ -457,9 +461,16 @@
 	GetRef(context.Context, *GetRefRequest) (*GetRefResponse, error)
 	// GoFindTryWork finds trybot work for the coordinator to build & test.
 	GoFindTryWork(context.Context, *GoFindTryWorkRequest) (*GoFindTryWorkResponse, error)
-	// ListGoReleases lists Go releases. A release is considered to exist for
-	// each git tag named "goX", "goX.Y", or "goX.Y.Z", as long as it has a
-	// corresponding "release-branch.goX" or "release-branch.goX.Y" release branch.
+	// ListGoReleases lists Go releases sorted by version with latest first.
+	//
+	// A release is considered to exist for each git tag named "goX", "goX.Y", or
+	// "goX.Y.Z", as long as it has a corresponding "release-branch.goX" or
+	// "release-branch.goX.Y" release branch.
+	//
+	// ListGoReleases returns only the latest patch versions of releases which
+	// are considered supported per policy. For example, Go 1.12.6 and 1.11.11.
+	// The response is guaranteed to have two versions, otherwise an error
+	// is returned.
 	ListGoReleases(context.Context, *ListGoReleasesRequest) (*ListGoReleasesResponse, error)
 }
 
diff --git a/maintner/maintnerd/apipb/api.proto b/maintner/maintnerd/apipb/api.proto
index dded094..756d5fa 100644
--- a/maintner/maintnerd/apipb/api.proto
+++ b/maintner/maintnerd/apipb/api.proto
@@ -72,12 +72,9 @@
   int32 minor = 2;
 }
 
-// By default, ListGoReleases returns only the latest patches
-// of releases that are considered supported per policy.
 message ListGoReleasesRequest {}
 
 message ListGoReleasesResponse {
-  // Releases are Go releases, sorted by version with latest first.
   repeated GoRelease releases = 1;
 }
 
@@ -106,8 +103,15 @@
   // GoFindTryWork finds trybot work for the coordinator to build & test.
   rpc GoFindTryWork(GoFindTryWorkRequest) returns (GoFindTryWorkResponse);
 
-  // ListGoReleases lists Go releases. A release is considered to exist for
-  // each git tag named "goX", "goX.Y", or "goX.Y.Z", as long as it has a
-  // corresponding "release-branch.goX" or "release-branch.goX.Y" release branch.
+  // ListGoReleases lists Go releases sorted by version with latest first.
+  //
+  // A release is considered to exist for each git tag named "goX", "goX.Y", or
+  // "goX.Y.Z", as long as it has a corresponding "release-branch.goX" or
+  // "release-branch.goX.Y" release branch.
+  //
+  // ListGoReleases returns only the latest patch versions of releases which
+  // are considered supported per policy. For example, Go 1.12.6 and 1.11.11.
+  // The response is guaranteed to have two versions, otherwise an error
+  // is returned.
   rpc ListGoReleases(ListGoReleasesRequest) returns (ListGoReleasesResponse);
 }