cue: some API adjustments for new-style definitions

The API is now rather unsuitable for handling definitions.
Add some temporary workarounds until we have a new API.

Also updates some old-style defintions to new style.

Change-Id: Ib5c3210016aca971c45c7eddbc9dcb65f7fdc4e1
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/6000
Reviewed-by: Marcel van Lohuizen <mpvl@google.com>
diff --git a/pkg/tool/os/doc.go b/pkg/tool/os/doc.go
index b32321f..b4a66c1 100644
--- a/pkg/tool/os/doc.go
+++ b/pkg/tool/os/doc.go
@@ -6,10 +6,10 @@
 //
 //     // A Value are all possible values allowed in flags.
 //     // A null value unsets an environment variable.
-//     Value :: bool | number | *string | null
+//     Value: bool | number | *string | null
 //
 //     // Name indicates a valid flag name.
-//     Name :: !="" & !~"^[$]"
+//     Name: !="" & !~"^[$]"
 //
 //     // Setenv defines a set of command line flags, the values of which will be set
 //     // at run time. The doc comment of the flag is presented to the user in help.
@@ -19,14 +19,14 @@
 //     Setenv: {
 //         $id: "tool/os.Setenv"
 //
-//         [Name]: Value
+//         {[Name]: Value}
 //     }
 //
 //     // Getenv gets and parses the specific command line variables.
 //     Getenv: {
 //         $id: "tool/os.Getenv"
 //
-//         [Name]: Value
+//         {[Name]: Value}
 //     }
 //
 //     // Environ populates a struct with all environment variables.
@@ -37,7 +37,7 @@
 //         // Individual entries may be specified ahead of time to enable
 //         // validation and parsing. Values that are marked as required
 //         // will fail the task if they are not found.
-//         [Name]: Value
+//         {[Name]: Value}
 //     }
 //
 //     // Clearenv clears all environment variables.
diff --git a/pkg/tool/os/os.cue b/pkg/tool/os/os.cue
index 6881bd9..56e1724 100644
--- a/pkg/tool/os/os.cue
+++ b/pkg/tool/os/os.cue
@@ -1,11 +1,11 @@
 // Copyright 2019 The CUE Authors
-// 
+//
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
-// 
+//
 //     http://www.apache.org/licenses/LICENSE-2.0
-// 
+//
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -16,10 +16,10 @@
 
 // A Value are all possible values allowed in flags.
 // A null value unsets an environment variable.
-Value :: bool | number | *string | null
+Value: bool | number | *string | null
 
 // Name indicates a valid flag name.
-Name :: !="" & !~"^[$]"
+Name: !="" & !~"^[$]"
 
 // Setenv defines a set of command line flags, the values of which will be set
 // at run time. The doc comment of the flag is presented to the user in help.