fix(example): remove usage of ++++ in example

* If we follow our example (copy paste), we don't reproduce the right behavior.

preview-src/admonitions.adoc

@@ -109,17 +109,17 @@ If you installed the CLI and the default site generator globally, you can upgrad
 
 .Click to see the *source code*
 [%collapsible]
-====
+========
 [source,text]
 ----
 [TIP]
-++++
+====
 If you installed the CLI and the default site generator globally, you can upgrade both of them with the same command.
 
  $ npm i -g @antora/cli @antora/site-generator-default
-++++
-----
 ====
+----
+========
 
 
 == Admonition with link and code
@@ -131,16 +131,16 @@ If you installed the CLI and the default site generator globally, you can upgrad
 
 .Click to see the *source code*
 [%collapsible]
-====
+========
 [source,asciidoc]
 ----
 [NOTE]
-++++
+====
 *Lorem Ipsum* is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. `And here is some code!`. xref:nothing[And a Link!].
-++++
+====
 
 ----
-====
+========
 
 
 [NOTE.bonitacloud,caption=Bonita cloud]
@@ -194,23 +194,19 @@ Don't forget this step!
 
 .Click to see the *source code*
 [%collapsible]
-====
+========
 [source,asciidoc]
 ----
 . blabla
 +
 [IMPORTANT]
-++++
+====
 Don't forget this step!
-++++
+====
 +
 . blabla
 ----
-====
-
-
----
-
+========
 
 * blabla
 ** Sous blabla
@@ -225,21 +221,21 @@ Watch out!
 
 .Click to see the *source code*
 [%collapsible]
-====
+========
 [source,asciidoc]
 ----
 * blabla
 ** Sous blabla
 +
 [WARNING]
-++++
+====
 Watch out!
-++++
+====
 +
 ** Sous blabla
 * blabla
 ----
-====
+========
 
 
 
@@ -259,11 +255,11 @@ Watch out!
 ====
 .Click to see the *source code*
 [%collapsible]
-====
+========
 [source,asciidoc]
 ----
 [TIP]
-++++
+====
 |===
 | Nom | Couleur de cheveux
 
@@ -273,9 +269,9 @@ Watch out!
 | Mr propre
 | _Chauve :'(_
 |===
-++++
-----
 ====
+----
+========
 
 
 
@@ -299,14 +295,14 @@ Watch out!
 
 .Click to see the *source code*
 [%collapsible]
-====
+========
 [source,asciidoc]
 ----
 . blabla
 . blabla
 +
 [CAUTION]
-++++
+====
 |===
 | Nourriture | Comestible
 
@@ -316,11 +312,11 @@ Watch out!
 | Brocolis
 | Non
 |===
-++++
+====
 +
 . blabla
 ----
-====
+========
 
 [NOTE]
 ====

preview-src/code.adoc

@@ -21,9 +21,9 @@ Uglify can only work with buffers, not streams.
 [%collapsible]
 ====
 [source,asciidoc]
-----
+--------
 [source,js]
-++++
+----
 vfs
   .src('js/vendor/*.js', { cwd: 'src', cwdbase: true, read: false })
   .pipe(tap((file) => { // <1>
@@ -32,11 +32,11 @@ vfs
   .pipe(buffer()) // <2>
   .pipe(uglify())
   .pipe(gulp.dest('build'))
-++++
+----
 <1> The tap function is used to wiretap the data in the pipe.
 <2> Wrap each streaming file in a buffer so the files can be processed by uglify.
 Uglify can only work with buffers, not streams.
-----
+--------
 [NOTE]
 ****
 <1> should be replaced by `<1>` (same thing for <2>)
@@ -55,12 +55,12 @@ alias ducksort=""du -cks * | sort -n""
 [%collapsible]
 ====
 [source,asciidoc]
-----
+--------
 [source,shell]
-++++
+----
 alias ducksort=""du -cks * | sort -n""
-++++
 ----
+--------
 ====
 
 == XML
@@ -79,9 +79,9 @@ alias ducksort=""du -cks * | sort -n""
 [%collapsible]
 ====
 [source,asciidoc]
-----
+--------
 [source,xml]
-++++
+----
 <root>
     <branch>
         <leafs length="130">
@@ -89,8 +89,8 @@ alias ducksort=""du -cks * | sort -n""
         </leafs>
     </branch>
 </root>
-++++
 ----
+--------
 ====
 
 
@@ -143,11 +143,14 @@ Same check but when code is in a `collapsible`
 .Click to see code
 [%collapsible]
 ====
+[source,asciidoc]
+--------
 [source, Java]
 ----
 while (true) {
   System.out.println("toto"); <1>
 }
 ----
+--------
 <1> The word `toto` is commonly used in examples, it probably refers to our inner self.
 ====

preview-src/media.adoc

@@ -34,7 +34,6 @@ image:multirepo-ssg.svg[Multirepo SSG,200,float=right]
 .Click to see the *source code*
 [%collapsible]
 ====
-[source,as
 [source,asciidoc]
 ----
 image:multirepo-ssg.svg[Multirepo SSG,200,float=right]