Doc: Fix issues in global documentation template

The qt-html-templates-offline.qdocconf includes
html-header-offline.qdocconf, which defines `HTML.stylesheets`,
the files to copy to /style subfolder in the output directory.

This variable was then later incorrectly redefined directly in
qt-html-templates-offline, missing one file, `tech_preview.svg`.
This file is used in CSS only, not in documentation sources, so
QDoc did not warn about the omission.

Remove duplicate definitions, and move all variables that do not
relate to HTML headers away from html-header-offline.

In passing, clean up formatting of the related definitions and
fix incorrect paths passed to `DocBook.extraimages'.

Pick-to: 6.10 6.8
Change-Id: I2428aaa8eb5871ec9757f74695096bc42664f1f2
Reviewed-by: Topi Reinio <[email protected]>

2 files changed, 28 insertions, 35 deletions

diff --git a/doc/global/html-header-offline.qdocconf b/doc/global/html-header-offline.qdocconf
index ffce22eeeec..97e13313785 100644
--- a/doc/global/html-header-offline.qdocconf
+++ b/doc/global/html-header-offline.qdocconf
@@ -1,14 +1,16 @@
 #Default HTML header for QDoc builds.
 
-#specify the CSS file used by this template
-HTML.stylesheets = template/style/offline.css \
-                   template/style/offline-dark.css \
-                   template/style/tech_preview.svg
-
-#for including files into the qch file
-qhp.extraFiles += style/offline.css \
-                  style/offline-dark.css \
-                  style/tech_preview.svg
+# CSS used by this template (copied to <outputdir>/style)
+HTML.stylesheets += \
+    template/style/offline.css \
+    template/style/offline-dark.css \
+    template/style/tech_preview.svg
+
+# Files (relative to the output directory) to include into the qch file
+qhp.extraFiles += \
+    style/offline.css \
+    style/offline-dark.css \
+    style/tech_preview.svg
 
 HTML.headerstyles = \
     "  <link rel=\"stylesheet\" type=\"text/css\" href=\"style/offline.css\" />\n"
diff --git a/doc/global/qt-html-templates-offline.qdocconf b/doc/global/qt-html-templates-offline.qdocconf
index 00fc58ba666..7cc8651bd33 100644
--- a/doc/global/qt-html-templates-offline.qdocconf
+++ b/doc/global/qt-html-templates-offline.qdocconf
@@ -8,34 +8,25 @@ defines                  += offlinedocs
 #uncomment if navigation bar is not wanted
 #HTML.nonavigationbar      = "true"
 
-HTML.stylesheets = template/style/offline.css \
-                   template/style/offline-dark.css
-HTML.extraimages += template/images/ico_out.png \
-                    template/images/btn_prev.png \
-                    template/images/btn_next.png \
-                    template/images/bullet_dn.png \
-                    template/images/bullet_sq.png \
-                    template/images/bgrContent.png
+# Images used only in CSS or macros that are copied to <outputdir>/images
+{HTML.extraimages,DocBook.extraimages} += \
+    template/images/ico_out.png \
+    template/images/btn_prev.png \
+    template/images/btn_next.png \
+    template/images/bullet_dn.png \
+    template/images/bullet_sq.png \
+    template/images/bgrContent.png
 
-sourcedirs += includes
-
-#specify which files in the output directory should be packed into the qch file.
-qhp.extraFiles +=   style/offline.css \
-                    style/offline-dark.css \
-                    images/ico_out.png \
-                    images/btn_prev.png \
-                    images/btn_next.png \
-                    images/bullet_dn.png \
-                    images/bullet_sq.png \
-                    images/bgrContent.png
+# Files (relative to the output directory) to include into the qch file
+qhp.extraFiles += \
+    images/ico_out.png \
+    images/btn_prev.png \
+    images/btn_next.png \
+    images/bullet_dn.png \
+    images/bullet_sq.png \
+    images/bgrContent.png
 
-DocBook.extraimages += \
-                    images/ico_out.png \
-                    images/btn_prev.png \
-                    images/btn_next.png \
-                    images/bullet_dn.png \
-                    images/bullet_sq.png \
-                    images/bgrContent.png
+sourcedirs += includes
 
 # By default, include override definitions for a simplified template/CSS,
 # suited for rendering HTML with QTextBrowser. Comment out this line to