Merge branch 'ua/os-version-capability'

The value of "uname -s" is by default sent over the wire as a part
of the "version" capability.

* ua/os-version-capability:
  agent: advertise OS name via agent capability
  t5701: add setup test to remove side-effect dependency
  version: extend get_uname_info() to hide system details
  version: refactor get_uname_info()
  version: refactor redact_non_printables()
  version: replace manual ASCII checks with isprint() for clarity

connect.c

@@ -624,7 +624,7 @@ const char *parse_feature_value(const char *feature_list, const char *feature, s
 					*offset = found + len - orig_start;
 				return value;
 			}
-			/* feature with a value (e.g., "agent=git/1.2.3") */
+			/* feature with a value (e.g., "agent=git/1.2.3-Linux") */
 			else if (*value == '=') {
 				size_t end;