Fix some typo in README

Fixes #263

README.asciidoc

@@ -301,7 +301,6 @@ Changes
             in place of line breaks
 
  * `>`: indent selected lines
- * `<`: deindent selected lines
  * `alt->`: indent selected lines, including empty lines
  * `<`: deindent selected lines
  * `alt-<`: deindent selected lines, do not remove incomplete
@@ -892,6 +891,10 @@ and
 :rmhl <highlighter_id>
 ----------------------
 
+`highlighter_id` is a name generated by the highlighter specified with `highlighter_name`,
+possibly dependent on the parameters. Use command completion on rmhl to see the existing
+highlighters id.
+
 general highlighters are:
 
  * `regex <ex> <capture_id>:<face>...`: highlight a regex, takes the regex as