doc: improve various BLOCKSIZE and SIZE help

* doc/coreutils.texi (multiplierSuffixes): Mention that
the suffix can be specified without a leading number
* src/split.c (usage): Refactor SIZE help to within a function
* src/truncate.c (usage): Likewise
* src/ls.c (usage): Likewise
* src/df.c (usage): Likewise. Also add a function with BLOCKSIZE help
* src/du.c (usage): Likewise.
* src/system.h: Define 2 functions to emit common help text
This was prompted by https://bugzilla.redhat.com/show_bug.cgi?id=511188

1 files changed, 2 insertions, 4 deletions

diff --git a/src/du.c b/src/du.c
index 9da901a62..321d30feb 100644
--- a/src/du.c
+++ b/src/du.c
@@ -330,10 +330,8 @@ Mandatory arguments to long options are mandatory for short options too.\n\
 "), stdout);
       fputs (HELP_OPTION_DESCRIPTION, stdout);
       fputs (VERSION_OPTION_DESCRIPTION, stdout);
-      fputs (_("\n\
-SIZE may be (or may be an integer optionally followed by) one of following:\n\
-kB 1000, K 1024, MB 1000*1000, M 1024*1024, and so on for G, T, P, E, Z, Y.\n\
-"), stdout);
+      emit_blocksize_note ("DU");
+      emit_size_note ();
       emit_bug_reporting_address ();
     }
   exit (status);