Fix the paragraph on tag groups as regular expressions.

Reword the paragraph and fix the regexps to include
the requisite @ signs.

doc/org.texi

@@ -5200,23 +5200,22 @@ When setting @code{org-tag-alist} you can use @code{:startgroup} &
 @code{:endgroup} instead of @code{:startgrouptag} & @code{:endgrouptag} to
 make the tags mutually exclusive.
 
-Furthermore; The members of a @emph{group tag} can also be regular
-expression, creating the possibility of more dynamic and rule-based
-tag-structure.  The regular expressions in the group must be marked up within
-@{ @}.  Example use, to expand on the example given above:
+Furthermore, the members of a @emph{group tag} can also be regular
+expressions, creating the possibility of a more dynamic and rule-based
+tag structure.  The regular expressions in the group must be specified
+within @{ @}.  Here is an expanded example:
 
 @example
-#+TAGS: [ Vision : @{V@.+@} ]
-#+TAGS: [ Goal : @{G@.+@} ]
-#+TAGS: [ AOF : @{AOF@.+@} ]
-#+TAGS: [ Project : @{P@.+@} ]
+#+TAGS: [ Vision : @{V@@@.+@} ]
+#+TAGS: [ Goal : @{G@@@.+@} ]
+#+TAGS: [ AOF : @{AOF@@@.+@} ]
+#+TAGS: [ Project : @{P@@@.+@} ]
 @end example
 
 Searching for the tag @samp{Project} will now list all tags also including
-regular expression matches for @samp{P@@.+}.  Similar for tag-searches on
-@samp{Vision}, @samp{Goal} and @samp{AOF}.  This can be good for example if
-tags for a certain project is tagged with a common project-identifier,
-i.e. @samp{P@@2014_OrgTags}.
+regular expression matches for @samp{P@@@.+}, and similarly for tag searches on
+@samp{Vision}, @samp{Goal} and @samp{AOF}.  For example, this would work well
+for a project tagged with a common project-identifier, e.g. @samp{P@@2014_OrgTags}.
 
 @kindex C-c C-x q
 @vindex org-group-tags