Change JSON encodings of some types.

- For LineEnding use lowercase constructors, e.g. `crlf`, `native`.
  This was the original intent, but there was a bug in the
  implementation.
- For HTMLSlideVariant use lowercase constructors.
- For ReaderOptions use e.g. `default-image-extension`
  instead of `readerDefaultImageExtension` for field names.
- For Extension, use e.g. `tex_math_dollars` instead of
  `Ext_tex_math_dollars` as constructor.
- For Extensions, use an array of Extensions, instead of
  an object wrapping the tag `Extensions` and an integer.
  (The representation is not supposed to be part of the
  public API.)
- For Opt, use field names like `tab-stop` instead of `optTabStop`.

1 files changed, 9 insertions, 9 deletions

diff --git a/doc/filters.md b/doc/filters.md
index 004a83b7d..c921fc007 100644
--- a/doc/filters.md
+++ b/doc/filters.md
@@ -460,36 +460,36 @@ filter.
 
     Object fields:
 
-    `readerAbbreviations`
+    `abbreviations`
     :   set of known abbreviations (array of strings).
 
-    `readerColumns`
+    `columns`
     :   number of columns in terminal; an integer.
 
-    `readerDefaultImageExtension`
+    default-image-extension`
     :   default extension for images; a string.
 
-    `readerExtensions`
+    `extensions`
     :   integer representation of the syntax extensions bit
         field.
 
-    `readerIndentedCodeClasses`
+    `indented-code-classes`
     :   default classes for indented code blocks; array of
         strings.
 
-    `readerStandalone`
+    `standalone`
     :   whether the input was a standalone document with header;
         either `true` or `false`.
 
-    `readerStripComments`
+    `strip-comments`
     :   HTML comments are stripped instead of parsed as raw HTML;
         either `true` or `false`.
 
-    `readerTabStop`
+    `tab-stop`
     :   width (i.e. equivalent number of spaces) of tab stops;
         integer.
 
-    `readerTrackChanges`
+    `track-changes`
     :   track changes setting for docx; one of
         `"accept-changes"`, `"reject-changes"`, and
         `"all-changes"`.