clarify that a negated tag selects all lines that do not contain a tag directive

CHANGELOG.adoc

@@ -8,6 +8,7 @@ https://github.com/asciidoctor/asciidoc-docs/commits/main[commit history].
 
 Fixed::
 * Rewrite much of link-macro-attribute-parsing.adoc to reflect the simplified parsing behavior implemented in https://github.com/asciidoctor/asciidoctor/issues/2059.
+* Clarify that a negated tag selects all lines except for those lines containing a tag directive (not simply all lines as it previously suggested)
 
 == Published Q4 2020
 

modules/directives/pages/include-tagged-regions.adoc

@@ -129,5 +129,6 @@ Here are some of the permutations that you can use:
 
 There are also some shorthands if only exclusions are specified:
 
-`!foo`:: Equivalent to `**;!foo`; an exclusion without an inclusion implicitly starts by selecting all the lines.
+`!foo`:: Equivalent to `**;!foo`; an exclusion without an inclusion implicitly starts by selecting all the lines that do not contain a tag directive.
+
 `!*`:: Equivalent to `+**;!*+`; only selects regions that are not tagged.