transport: change default NFD Unix socket path

Refs: #5304
Change-Id: Ice56dd716abd808896e5cd7609398e26c15ffa3a
diff --git a/client.conf.sample b/client.conf.sample
index b1debc8..453a8ed 100644
--- a/client.conf.sample
+++ b/client.conf.sample
@@ -1,27 +1,28 @@
-; "transport" specifies Face's default transport connection.
-; The value can be a "unix:" or "tcp4:" Face URI.
+; "transport" specifies the default transport connection used by the client-side face to communicate
+; with a (local or remote) NDN forwarder. The value must be a Face URI with a Unix or TCP scheme.
 ;
 ; For example:
-;   unix:///var/run/nfd.sock
+;   unix:///tmp/nfd/nfd.sock
 ;   tcp://192.0.2.1
 ;   tcp4://example.com:6363
+;   tcp6://[2001:db8::1]:6363
 ;
-; The default value of this field is platform-dependent, being unix:///run/nfd.sock on Linux and
-; unix:///var/run/nfd.sock on other platforms.
+; The default value of this field is platform-dependent, being "unix:///run/nfd/nfd.sock" on Linux
+; and "unix:///var/run/nfd/nfd.sock" on other platforms.
 ;
-;transport=unix:///var/run/nfd.sock
+;transport=unix:///var/run/nfd/nfd.sock
 
-; "pib" determines which Public Info Base (PIB) should used by default in applications.
+; "pib" determines which Public Information Base (PIB) should used by default in applications.
 ; If "pib" is not specified, a platform-dependent default will be used.
 ; If "pib" is specified, it may have a value of:
-;   pib-sqlite3
+;   - "pib-sqlite3"
 ;
 ;pib=pib-sqlite3
 
 ; "tpm" determines which Trusted Platform Module (TPM) should used by default in applications.
 ; If "tpm" is not specified, a platform-dependent default will be used.
 ; If "tpm" is specified, it may have a value of:
-;   tpm-osxkeychain (default on macOS)
-;   tpm-file (default in operating systems other than macOS)
+;   - "tpm-osxkeychain"  (default on macOS)
+;   - "tpm-file"         (default on all other platforms)
 ;
 ;tpm=tpm-file