Add small documentation README

Author: graeme-a-stewart

docs/README.md

@@ -0,0 +1,51 @@
+# Generating and Previewing Documentation
+
+## Adding Documentation
+
+`Documenter.jl` is used to generate package documentation. 
+
+The general guidelines are to have documentation split into meaningful sections,
+none of which are too long. If a new functionality is added then create a new
+documentation page in `src`. Then map that markdown file to the a section in the
+documentation in `make.jl` in the `pages` map.
+
+## Previewing Documenation
+
+From the `docs` directory:
+
+```julia
+julia --project
+               _
+   _       _ _(_)_     |  Documentation: https://docs.julialang.org
+  (_)     | (_) (_)    |
+   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
+  | | | | | | |/ _` |  |
+  | | |_| | | | (_| |  |  Version 1.11.1 (2024-10-16)
+ _/ |\__'_|_|_|\__'_|  |  Official https://julialang.org/ release
+|__/                   |
+
+julia> include("make.jl")
+[ Info: SetupBuildDirectory: setting up build directory.
+[ Info: Doctest: running doctests.
+[ Info: ExpandTemplates: expanding markdown templates.
+[ Info: CrossReferences: building cross-references.
+[ Info: CheckDocument: running document checks.
+[ Info: Populate: populating indices.
+[ Info: RenderDocument: rendering document.
+[ Info: HTMLWriter: rendering HTML pages.
+┌ Warning: Generated HTML over size_threshold_warn limit: lib/internal.md
+│     Generated file size: 128.16 (KiB)
+│     size_threshold_warn: 100.0 (KiB)
+│     size_threshold:      200.0 (KiB)
+│     HTML file:           lib/internal/index.html
+└ @ Documenter.HTMLWriter ~/.julia/packages/Documenter/C1XEF/src/html/HTMLWriter.jl:1828
+[ Info: Automatic `version="0.4.3"` for inventory from ../Project.toml
+┌ Warning: Documenter could not auto-detect the building environment. Skipping deployment.
+└ @ Documenter ~/.julia/packages/Documenter/C1XEF/src/deployconfig.jl:76
+
+julia> using LiveServer
+
+julia> LiveServer.serve(dir="build/")
+✓ LiveServer listening on http://localhost:8000/ ...
+  (use CTRL+C to shut down)
+```