basic: introduce basic one-shot INI-style decoder

Signed-off-by: Alejandro Mery <amery@jpi.io>

README.md

@@ -16,6 +16,7 @@ of stricter parsers of similar form.
 
 [godoc-lexer]: https://pkg.go.dev/asciigoat.org/core/lexer
 [godoc-parser-parser]: https://pkg.go.dev/asciigoat.org/ini/parser#Parser
+[godoc-basic-parser]: https://pkg.go.dev/asciigoat.org/ini/basic#Decode
 
 [wikipedia-dosini]: https://en.wikipedia.org/wiki/INI_file
 
@@ -25,6 +26,15 @@ of stricter parsers of similar form.
 [`asciigoat`'s lexer][godoc-lexer] to process an `INI`-style document
 emiting tokens and errors via callbacks.
 
+## Basic Parser
+
+[`basic.Decode()`][godoc-basic-parser] provies a one-shot decoder
+that returns a structured document for you to post-process.
+
+To allow for correct handling of repetition of section and field names downstream,
+it uses arrays instead of maps, and makes almost no judgment
+about what section or field names are acceptable.
+
 ## Other Implementations
 
 Other implementations exist, and they are mature and feature-rich, but they