document how to include= a path with a space in it

POSIX character classes allowed in globs was a surprise, but just
happened to fall out of the implementation in a way that seems
to behave correctly.

mdwn2man has to be tweaked to render the example properly.
The line I modified is the one that strips ikiwiki wikilinks out of the
man page.

Sponsored-by: Graham Spencer on Patreon

Build/mdwn2man

@@ -7,7 +7,7 @@ my $section=shift;
 print ".TH $prog $section\n";
 
 while (<>) {
-	s{(\\?)\[\[([^\s\|\]]+)(\|[^\s\]]+)?\]\]}{$1 ? "[[$2]]" : $2}eg;
+	s{(\\?)\[\[([^:\s\|\]]+)(\|[^\s\]]+)?\]\]}{$1 ? "[[$2]]" : $2}eg;
 	s/\`([^\`]*)\`/\\fB$1\\fP/g;
 	s/\`//g;
 	s/^ *\./\\&./g;

doc/bugs/preferred_content__58___include_statement_does_not_allow_spaces_in_filenames.mdwn

@@ -29,3 +29,5 @@ upgrade supported from repository versions: 0 1 2 4
 The only workaround I found is to use a glob for the filepath which only works for the first space: *include='pictures/dir\*'*.
 
 [[!tag confirmed]]
+
+> [[fixed|done]] by documenting the `[[:space:]]` workaround. --[[Joey]]

doc/bugs/preferred_content__58___include_statement_does_not_allow_spaces_in_filenames/comment_4_7a8f1ba849f6e6f6072c39bdbff49405._comment

@@ -0,0 +1,13 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 4"""
+ date="2023-05-15T19:40:59Z"
+ content="""
+Thanks @aurtzy, that is a great observation! And a feature I was not
+actually aware of.
+
+So, I think that documenting this should be sufficient.
+
+(The `glob(7)` man page does document POSIX character classes as working in
+globs, so this is a fairly standard thing.)
+"""]]

doc/git-annex-preferred-content.mdwn

@@ -40,6 +40,13 @@ elsewhere to allow removing it).
   files relative to the current directory, preferred content expressions
   match files relative to the top of the git repository.
 
+  A glob is something like `foo.*` or `b?r`. 
+  Globs can also contain character classes, 
+  like `foo[Bb]ar`, as well as additional POSIX character classes like
+  `[[:space:]]`. Which is useful, since a glob in a preferred content
+  expression cannot contain spaces. See the `glob(7)` man page for more
+  about globs.
+
   For example, suppose you put files into `archive` directories
   when you're done with them. Then you could configure your laptop to prefer
   to not retain those files, like this: `exclude=*/archive/*`
@@ -130,6 +137,13 @@ elsewhere to allow removing it).
   matches the glob. The values of metadata fields are matched case
   insensitively.
 
+  A glob is something like `foo.*` or `b?r`. 
+  Globs can also contain character classes, 
+  like `foo[Bb]ar`, as well as additional POSIX character classes like
+  `[[:space:]]`. Which is useful, since a glob in a preferred content
+  expression cannot contain spaces. See the `glob(7)` man page for more
+  about globs.
+
   To match a tag "done", use `metadata=tag=done`
 
   To match author metadata, use `metadata=author=*Smith`