More surgery

- Remove .eslintignore and .prettierignore files
- Convert from an mdast util to a remark plugin for easier use with
  unified.js processors
- Rename package to remark-astro
- Rename data field from `astromd` to `astro` for consistency and
  easier typing and pronunciation
- Remove documentation of supported syntax from README. We will
  develop better user documentation elsewhere

.gitignore

@@ -1,6 +1,6 @@
 node_modules
 /coverage
-/*.js
+/index.js
 *.d.ts
 .eslintcache
 *.tgz

README.md

@@ -1,8 +1,8 @@
-[![codecov](https://codecov.io/gh/nasa-gcn/mdast-astromd/branch/main/graph/badge.svg?token=3ID7X7XNNQ)](https://codecov.io/gh/nasa-gcn/mdast-astromd)
+[![codecov](https://codecov.io/gh/nasa-gcn/remark-astro/branch/main/graph/badge.svg?token=3ID7X7XNNQ)](https://codecov.io/gh/nasa-gcn/remark-astro)
 
-# mdast-astromd
+# remark-astro
 
-This is a plugin for [mdast](https://github.com/syntax-tree/mdast) for parsing Astro Flavored Markdown, a dialect of [Markdown](https://www.markdownguide.org) for rapid astronomy communications.
+This is a plugin for [remark](https://github.com/remarkjs/remark) for parsing Astro Flavored Markdown, a dialect of [Markdown](https://www.markdownguide.org) for rapid astronomy communications.
 
 Astro Flavored Markdown detects dates, times, sky coordinates, and bibliographic references. Astro Flavored Markdown data is tagged in the [mdast](https://github.com/syntax-tree/mdast) syntax tree for later enrichment.
 
@@ -11,7 +11,7 @@ An Astro Flavored Markdown node is just an mdast [Text](https://github.com/synta
 ```ts
 export interface AstroText extends Text {
   data: {
-    astromd: {
+    astro: {
       /** Astro Flavored Markdown data type */
       type: string
       /** Normalized value */
@@ -21,12 +21,4 @@ export interface AstroText extends Text {
 }
 ```
 
-Astro Flavored Markdown supports the following types.
-
-## datetime
-
-A UTC date with an optional time, normalized to [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601).
-
-## gcn-circular
-
-A reference to a GCN Circular.
+For supported syntax, see the [src/replacements](src/replacements) directory. In each direcetory there is a file called `test.md` illustrating the Markdown syntax and a file called `test.json` containing the resulting syntax tree.