[#3522] Fix whitespace

changelog_unreleased/.template

@@ -1,6 +1,6 @@
 [category]		author
 	Multiline description up to 70 columns ------------------------>|
-    Available categories: bug, build, doc, func, sec, perf.
+	Available categories: bug, build, doc, func, sec, perf.
-    Add * next to the category end bracket to mark change as backward
+	Add * next to the category end bracket to mark change as backward
-    incompatible. Example: [func]*
+	incompatible. Example: [func]*
 	(Gitlab #0000)

doc/devel/changelog.dox

@@ -17,27 +17,27 @@ the file should include the GitLab issue number to ensure the filename is
 unique for all merge requests.
 The content of the file should omit the entry number. The format is:
 
-@code
+@code{.unparsed}
 [category][* if the changes are backward incompatible]		[author]
-    [multi-line description, indented]
+	[multi-line description, indented]
-    [GL issue number, indented]
+	[GL issue number, indented]
 [optional empty line]
 @endcode
 
 The GitLab issue number must be constructed as follows:
 
-@code
+@code{.unparsed}
 (Gitlab #XXXX)
 @endcode
 
 where XXXX is the GitLab issue number.
 Example:
 
-@code
+@code{.unparsed}
 [build]		slawek
-    Changed the convention of preparing the ChangeLog file to avoid merge
+	Changed the convention of preparing the ChangeLog file to avoid merge
-    request conflicts on this file.
+	request conflicts on this file.
-    (Gitlab #3522)
+	(Gitlab #3522)
 
 @endcode