Update get_column docs

Fixes tree-sitter#1405

Author: maxbrunsfeld

docs/section-3-creating-parsers.md

@@ -674,7 +674,7 @@ This function is responsible for recognizing external tokens. It should return `
 * **`TSSymbol result_symbol`** - The symbol that was recognized. Your scan function should *assign* to this field one of the values from the `TokenType` enum, described above.
 * **`void (*advance)(TSLexer *, bool skip)`** - A function for advancing to the next character. If you pass `true` for the second argument, the current character will be treated as whitespace.
 * **`void (*mark_end)(TSLexer *)`** - A function for marking the end of the recognized token. This allows matching tokens that require multiple characters of lookahead. By default (if you don't call `mark_end`), any character that you moved past using the `advance` function will be included in the size of the token. But once you call `mark_end`, then any later calls to `advance` will *not* increase the size of the returned token. You can call `mark_end` multiple times to increase the size of the token.
-* **`uint32_t (*get_column)(TSLexer *)`** - **(Experimental)** A function for querying the current column position of the lexer. It returns the number of unicode code points (not bytes) since the start of the current line.
+* **`uint32_t (*get_column)(TSLexer *)`** - A function for querying the current column position of the lexer. It returns the number of bytes (not characters) since the start of the current line.
 * **`bool (*is_at_included_range_start)(TSLexer *)`** - A function for checking if the parser has just skipped some characters in the document. When parsing an embedded document using the `ts_parser_set_included_ranges` function (described in the [multi-language document section][multi-language-section]), your scanner may want to apply some special behavior when moving to a disjoint part of the document. For example, in [EJS documents][ejs], the JavaScript parser uses this function to enable inserting automatic semicolon tokens in between the code directives, delimited by `<%` and `%>`.
 
 The third argument to the `scan` function is an array of booleans that indicates which of your external tokens are currently expected by the parser. You should only look for a given token if it is valid according to this array. At the same time, you cannot backtrack, so you may need to combine certain pieces of logic.