Export DocInput

FEATURE: Export `DocInput` class for feeding editor documents to a Lezer parser.

See https://discuss.codemirror.net/t/exporting-docinput-from-the-language-package/6506

src/README.md

@@ -28,6 +28,8 @@
 
 @LanguageDescription
 
+@DocInput
+
 ### Highlighting
 
 @HighlightStyle

src/index.ts

@@ -1,7 +1,7 @@
 export {language, Language, LRLanguage, Sublanguage, sublanguageProp, defineLanguageFacet,
         syntaxTree, ensureSyntaxTree, languageDataProp,
         ParseContext, LanguageSupport, LanguageDescription,
-        syntaxTreeAvailable, syntaxParserRunning, forceParsing} from "./language"
+        syntaxTreeAvailable, syntaxParserRunning, forceParsing, DocInput} from "./language"
 
 export {IndentContext, getIndentUnit, indentString, indentOnInput, indentService, getIndentation, indentRange, indentUnit,
         TreeIndentContext, indentNodeProp, delimitedIndent, continuedIndent, flatIndent} from "./indent"

src/language.ts

@@ -249,12 +249,15 @@ export function syntaxParserRunning(view: EditorView) {
   return view.plugin(parseWorker)?.isWorking() || false
 }
 
-// Lezer-style Input object for a Text document.
-class DocInput implements Input {
-  cursor: TextIterator
-  cursorPos = 0
-  string = ""
-
+/// Lezer-style
+/// [`Input`](https://lezer.codemirror.net/docs/ref#common.Input)
+/// object for a [`Text`](#state.Text) object.
+export class DocInput implements Input {
+  private cursor: TextIterator
+  private cursorPos = 0
+  private string = ""
+
+  /// Create an input object for the given document.
   constructor(readonly doc: Text) {
     this.cursor = doc.iter()
   }