[gimp] devel-docs: port g-ir-doc-tool hack-fix to autotools build.

[Jehan <jehanp src gnome org>]

commit 288a5f1c7eeb6e33b6df5ab74afcc73b6abb29f4
Author: Jehan <jehan girinstud io>
Date:   Sun Mar 27 17:26:35 2022 +0200

    devel-docs: port g-ir-doc-tool hack-fix to autotools build.
    
    I completely forgot to port the hack from commit 7123b6c466d to
    autotools as well!

 devel-docs/g-ir-docs/Makefile.am | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/devel-docs/g-ir-docs/Makefile.am b/devel-docs/g-ir-docs/Makefile.am
index 1e29a4c65c..63d2ad0ea2 100644
--- a/devel-docs/g-ir-docs/Makefile.am
+++ b/devel-docs/g-ir-docs/Makefile.am
@@ -5,6 +5,7 @@ Gimp-%-docs: $(top_builddir)/libgimp/Gimp-@GIMP_API_VERSION@.gir
                -I "$(top_builddir)/libgimp" --language=$*              \
                -o "$(builddir)/pages/$*/Gimp-$(GIMP_API_VERSION)"      \
                $<
+       sed -i 's/<\(Prefix\|Image\)/\&lt;\1/g' 
"$(builddir)/pages/$*/Gimp-$(GIMP_API_VERSION)/Gimp.Procedure.add_menu_path.page"
        $(YELP_BUILD) cache                                                             \
                -o "$(builddir)/pages/$*/Gimp-$(GIMP_API_VERSION)/index.cache"  \
                "$(builddir)/pages/$*/Gimp-$(GIMP_API_VERSION)/"