fix spell-check errors

tests/by-util/test_dd.rs

@@ -357,7 +357,7 @@ fn test_fullblock() {
             of!(&tmp_fn),
             "bs=128M",
             // Note: In order for this test to actually test iflag=fullblock, the bs=VALUE
-            // must be big enough to 'overwhelm' urandom's store of bytes.
+            // must be big enough to 'overwhelm' the urandom store of bytes.
             // Try executing 'dd if=/dev/urandom bs=128M count=1' (i.e without iflag=fullblock).
             // The stats should contain the line: '0+1 records in' indicating a partial read.
             // Since my system only copies 32 MiB without fullblock, I expect 128 MiB to be

tests/by-util/test_tr.rs

@@ -290,7 +290,7 @@ fn test_interpret_backslash_at_eol_literally() {
 #[cfg(not(target_os = "freebsd"))]
 fn test_more_than_2_sets() {
     new_ucmd!()
-        .args(&["'abcdefgh'", "'a", "'b'"])
+        .args(&["'abcdef'", "'a'", "'b'"])
         .pipe_in("hello world")
         .fails();
 }

tests/by-util/test_yes.rs

@@ -45,7 +45,7 @@ fn test_long_input() {
     // try something long.
     #[cfg(windows)]
     const TIMES: usize = 500;
-    let arg = "abcdefg".repeat(TIMES) + "\n";
+    let arg = "abcdef".repeat(TIMES) + "\n";
     let expected_out = arg.repeat(30);
     run(&[&arg[..arg.len() - 1]], expected_out.as_bytes());
 }