add help file for base64

src/uu/base64/base64.md

@@ -0,0 +1,15 @@
+# base64
+
+## Usage
+{} [OPTION]... [FILE]
+
+## About
+
+encode/decode data and print to standard output
+With no FILE, or when FILE is -, read standard input.
+
+The data are encoded as described for the base64 alphabet in RFC
+3548. When decoding, the input may contain newlines in addition
+to the bytes of the formal base64 alphabet. Use --ignore-garbage
+to attempt to recover from any other non-alphabet bytes in the
+encoded stream.

src/uu/base64/src/base64.rs

@@ -9,22 +9,12 @@
 use uu_base32::base_common;
 pub use uu_base32::uu_app;
 
-use uucore::{encoding::Format, error::UResult};
+use uucore::{encoding::Format, error::UResult, help_section};
 
 use std::io::{stdin, Read};
 
-static ABOUT: &str = "\
-encode/decode data and print to standard output
-With no FILE, or when FILE is -, read standard input.
-
-The data are encoded as described for the base64 alphabet in RFC
-3548. When decoding, the input may contain newlines in addition
-to the bytes of the formal base64 alphabet. Use --ignore-garbage
-to attempt to recover from any other non-alphabet bytes in the
-encoded stream.
-";
-
-const USAGE: &str = "{0} [OPTION]... [FILE]";
+const ABOUT: &str = help_section!("about");
+const USAGE: &str = help_section!("usage");
 
 #[uucore::main]
 pub fn uumain(args: impl uucore::Args) -> UResult<()> {