Fixup usage message formatting

src/bin/sfdoc

             "-l, --ls [MODULE]  list contents of MODULE if specified,"  \
             "                   otherwise of all modules"               \
             "-L, --lsmod        show list of modules"                   \
-            " --lsfun MODULE    show list of functions in MODULE"       \
-            " --lsvar MODULE    show list of variables in MODULE"       \
-            " --which MODULE    show path to MODULE file"               \
+            "--lsfun MODULE     show list of functions in MODULE"       \
+            "--lsvar MODULE     show list of variables in MODULE"       \
+            "--which MODULE     show path to MODULE file"               \
             "-s, --src MODULE   show MODULE source code"                \
             "-e, --export FMT MODULE   export MODULE documentation in"  \
             "                   format FMT: 'markdown', 'manpage' and"  \