correct syntax error and add test

Author: scivision

+stdlib/md5sum.m

@@ -2,7 +2,7 @@
 % requires: java
 function hash = md5sum(file)
 arguments
-  file {mustBeScalarText}
+  file {mustBeTextScalar}
 end
 
 hash = stdlib.file_checksum(file, "md5");

+stdlib/sha256sum.m

@@ -3,7 +3,7 @@
 
 function hash = sha256sum(file)
 arguments
-  file {mustBeScalarText}
+  file {mustBeTextScalar}
 end
 
 hash = stdlib.file_checksum(file, "SHA-256");

test/TestHash.m

@@ -24,6 +24,9 @@ function test_hash_text(tc, Ph)
 
 tc.verifyEqual(stdlib.file_checksum(fn, Ph{1}), Ph{2})
 
+switch Ph{1}
+  case 'md5', tc.verifyEqual(stdlib.md5sum(fn), Ph{2})
+  case 'sha-256', tc.verifyEqual(stdlib.sha256sum(fn), Ph{2})
 end