remove useless printf

(SC2116)

Signed-off-by: Lucas Larson <LucasLarson@riseup.net>

readme.adoc

@@ -100,7 +100,7 @@ plugin^] or you can just clone this repository, run the following command, and
 then restart your terminal:
 [source,zsh]
 $ printf '%s\n' '. /path/to/gunstage.plugin.zsh' \
-  >>"$(printf '%s\n' "${HOME-}"'/.'"${SHELL##*[-./]}"'rc')"
+  >>"${HOME-}"'/.'"${SHELL##*[-./]}"'rc'
 
 Requirements
 ~~~~~~~~~~~~