remove "Asciidoctor only" label in user docs

docs/modules/document/pages/doctypes.adoc

@@ -17,7 +17,6 @@ This doctype instructs the parser to recognize a special document header and sec
 See xref:asciidoctor:manpage-backend:index.adoc[] for details on how structure a man page using AsciiDoc and generate it with Asciidoctor.
 
 Inline (`inline`)::
-Asciidoctor only.
 There may be cases when you only want to apply inline AsciiDoc formatting to input text without wrapping it in a block element.
 For example, in the Asciidoclet project (AsciiDoc in Javadoc), only the inline formatting is needed for the text in Javadoc tags.
 // {asciidoclet-ref}[Asciidoclet project]

docs/modules/macros/pages/xref-validate.adoc

@@ -23,4 +23,4 @@ If you run Asciidoctor in verbose/pedantic mode on this document, it will send t
 asciidoctor: WARNING: invalid reference: foobar
 ....
 
-Asciidoctor only validates references within the same document (after includes are resolved).
+The AsciiDoc processor only validates references within the same document (after includes are resolved).

docs/modules/sections/pages/section-ref.adoc

@@ -47,7 +47,6 @@
 |`sectanchors`
 |NA
 |
-//Asciidoctor only
 
 |xref:ids.adoc[Section ID]
 |`sectids`
@@ -59,7 +58,6 @@
 |`sectlinks`
 |NA
 |
-//Asciidoctor only
 
 |xref:numbers.adoc[Section numbers] and xref:special-section-numbers.adoc[special section numbers]
 |`sectnums`
@@ -76,7 +74,6 @@
 |`options` or `%`
 |`untitled`
 |DocBook only; can only be set on special sections
-//Asciidoctor only
 |===
 
 == Section styles