[PATCH -perfbook v2 2/3] Silence warning msg from LaTeX while loading parnotes package

LaTeX2e <2024-06-01> emits warning on loading parnotes.sty saying:

    LaTeX Warning: Command `\theparnotemark' already defined -- not changed on input line 54.

This looks like a harmless warning.
As perfbook's build scripts treat "LaTeX Warning" as build error,
silence it by enabling a filter for this particular message.

Signed-off-by: Akira Yokosawa <[email protected]>
---
Unfortunately, parnotes doesn't have any maintainer assigned and it
is not clear if the issue can be taken care of soon.

---
 perfbook-lt.tex | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/perfbook-lt.tex b/perfbook-lt.tex
index ad4463be..3c6fb9f3 100644
--- a/perfbook-lt.tex
+++ b/perfbook-lt.tex
@@ -79,6 +79,9 @@
 \usepackage[split,makeindex]{splitidx}
 \usepackage[nottoc]{tocbibind}
 \usepackage[columns=3,totoc,indentunit=12pt,justific=raggedright,font=small,columnsep=.15in]{idxlayout}
+\RequirePackage[save]{silence}
+\WarningFilter[parnotes]{latex}{Command `\theparnotemark' already defined}
+\ActivateWarningFilters[parnotes]
 \usepackage{parnotes} % for footnotes in tabularx
 \usepackage[bookmarks=true,bookmarksnumbered=true,pdfborder={0 0 0},linktoc=all,pdfusetitle]{hyperref}
 \usepackage{footnotebackref} % to enable cross-ref of footnote
-- 
2.34.1