diff --git a/mk/docs.mk b/mk/docs.mk
index b27c8f23151..31fa315857e 100644
--- a/mk/docs.mk
+++ b/mk/docs.mk
@@ -19,8 +19,8 @@ HTML_DEPS :=
 
 BASE_DOC_OPTS := --from=markdown --standalone --toc --number-sections
 HTML_OPTS = $(BASE_DOC_OPTS) 	--to=html5  --section-divs --css=rust.css  \
-															--include-before-body=doc/version_info.html \
-															--include-in-header=doc/favicon.inc
+								--include-before-body=doc/version_info.html \
+								--include-in-header=doc/favicon.inc
 TEX_OPTS = $(BASE_DOC_OPTS) --to=latex
 EPUB_OPTS = $(BASE_DOC_OPTS) --to=epub