Remove diag table schema

Remove the diag table schema, as it has been moved to the
`gfdl_msd_schemas` repository. Add references to the schema and the new
repository to the diag manager's `README.md` and `diag_yaml_format.md`
files.

diag_manager/README.md

@@ -1,4 +1,4 @@
-The purpose of this document is to document the differences between the old diag manager and the new (modern) diag manager. 
+The purpose of this document is to document the differences between the old diag manager and the new (modern) diag manager.
 
 ## Contents
 - [1. Diag Table Format](README.md#1-diag-table-format)
@@ -10,7 +10,9 @@ The purpose of this document is to document the differences between the old diag
 - [7. History files data output "changes"](README.md#7-history-files-data-output-changes)
 
 ### 1. Diag Table Format
-The modern diag manager uses a YAML format instead of the legacy ascii table. A description of the YAML diag table can be found [here](diag_yaml_format.md).
+The modern diag manager uses a YAML format instead of the legacy ascii table. A description of the YAML diag table can
+be found [here](diag_yaml_format.md). A formal specification, in the form of a JSON schema, can be found in the
+[gfdl_msd_schemas](https://github.com/NOAA-GFDL/gfdl_msd_schemas) repository on Github.
 
 ### 2. Scalar Axis
 The old diag manager was adding a `scalar_axis` dimension of size 1 for scalar variables
@@ -70,7 +72,7 @@ This time_bounds variable is refernced as a variable attribute of time:
 ### 4. Subregional Files
 
 #### A. `is_subregional` global attribute:
-Subregional files will have a global NetCDF attribute `is_subregional = True` set for non-global history files. This attribute will be used in PP tools. 
+Subregional files will have a global NetCDF attribute `is_subregional = True` set for non-global history files. This attribute will be used in PP tools.
 
 #### B. Subregional dimension names:
 In some cases, the old diag manager was adding `sub0X` to the dimension names where X is a number greater than 1. This was causing problems in PP tools that were expecting the dimension to have `sub01` in the name. The new diag manager will not have this problem.

diag_manager/diag_yaml_format.md

@@ -14,6 +14,7 @@ The purpose of this document is to explain the diag_table yaml format.
 - [2.5 Global Meta Data Section](diag_yaml_format.md#25-global-meta-data-section)
 - [2.6 Sub_region Section](diag_yaml_format.md#26-sub_region-section)
 - [3. More examples](diag_yaml_format.md#3-more-examples)
+- [4. Schema](diag_yaml_format.md#4-schema)
 
 ### 1. Converting from legacy ascii diag_table format
 
@@ -340,3 +341,8 @@ diag_files:
   unlimdim: records
   write_file: false
 ```
+
+### 4. Schema
+A formal specification of the file format, in the form of a JSON schema, can be
+found in the [gfdl_msd_schemas](https://github.com/NOAA-GFDL/gfdl_msd_schemas)
+repository on Github.