[Doc] Add admonitions redirecting users to stable docs

doc/sphinx/develop/index.md

@@ -1,5 +1,10 @@
 # Develop
 
+```{caution}
+This page is a work in progress. For compilation instructions for Cantera 3.0, please
+see <a href="/install/compiling-install.html">this page</a>.
+```
+
 - Compilation instructions
 - Explanations of how the code works
 - Guides to introducing new models

doc/sphinx/index.md

@@ -1,5 +1,10 @@
 # Table of Contents
 
+```{caution}
+This page is a work in progress. For documentation and tutorials for Cantera 3.0, please
+see <a href="/index.html">this page</a>.
+```
+
 ```{toctree}
 :maxdepth: 1
 

doc/sphinx/install/index.md

@@ -1,5 +1,10 @@
 # Install
 
+```{caution}
+This page is a work in progress. For installation instructions for Cantera 3.0, please
+see <a href="/install/index.html">this page</a>.
+```
+
 ```{toctree}
 :maxdepth: 1
 

doc/sphinx/reference/index.md

@@ -3,6 +3,13 @@
 
 This pages provide detailed reference documentation for Cantera.
 
+```{caution}
+This page is a work in progress. For more complete documentation of the current Cantera
+release (Cantera 3.0), please see the
+<a href="/documentation/index.html">documentation index</a> and the
+<a href="science/index.html">Science & Theory Manual</a>.
+```
+
 ## Programming Reference
 
 These sections document the classes and functions that define the Cantera interface for

doc/sphinx/reference/science/reactors/index.md

@@ -1,5 +1,10 @@
 # Reactors and Reactor Networks
 
+```{caution}
+This page is a work in progress. For more complete documentation of the current Cantera
+release (Cantera 3.0), please see <a href="/science/reactors/reactors.html">this page</a>.
+```
+
 ## Reactors
 
 A Cantera *reactor* represents the simplest form of a chemically reacting system. It

doc/sphinx/userguide/index.md

@@ -1,7 +1,13 @@
 # User Guide
 
+```{caution}
+This page is a work in progress. For tutorials covering the current Cantera
+release (Cantera 3.0), please see <a href="/tutorials/index.html">this page</a>.
+```
+
 ## Introductory Tutorials
 
+
 {doc}`Getting Started with Python <python-tutorial>`
 
 * Task/goal-oriented guides