maint: convert `...' to '...' in --help output

All affected lines end with \ or \n\, so run this command
until it produces no new changes (4 times):
  git grep -E -l '`[^ ]+'\''.*\\' src \
    |xargs perl -pi -e 's/`([^ ]+'\''.*\\)/'\''$1/'

1 files changed, 1 insertions, 1 deletions

diff --git a/src/who.c b/src/who.c
index 00d463747..6514cce80 100644
--- a/src/who.c
+++ b/src/who.c
@@ -682,7 +682,7 @@ Print information about users who are currently logged in.\n\
       printf (_("\
 \n\
 If FILE is not specified, use %s.  %s as FILE is common.\n\
-If ARG1 ARG2 given, -m presumed: `am i' or `mom likes' are usual.\n\
+If ARG1 ARG2 given, -m presumed: 'am i' or 'mom likes' are usual.\n\
 "), UTMP_FILE, WTMP_FILE);
       emit_ancillary_info ();
     }