doc, inspector: note that the host is optional

Document that `node --inspect=${port}` is also a viable option.

PR-URL: #12149
Reviewed-By: Eugene Ostroukhov <eostroukhov@google.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/cli.md

@@ -94,7 +94,7 @@ Follows `require()`'s module resolution
 rules. `module` may be either a path to a file, or a node module name.
 
 
-### `--inspect[=host:port]`
+### `--inspect[=[host:]port]`
 <!-- YAML
 added: v6.3.0
 -->
@@ -106,7 +106,7 @@ and profile Node.js instances. The tools attach to Node.js instances via a
 tcp port and communicate using the [Chrome Debugging Protocol][].
 
 
-### `--inspect-brk[=host:port]`
+### `--inspect-brk[=[host:]port]`
 <!-- YAML
 added: v7.6.0
 -->

doc/node.1

@@ -93,14 +93,14 @@ Preload the specified module at startup. Follows `require()`'s module resolution
 rules. \fImodule\fR may be either a path to a file, or a node module name.
 
 .TP
-.BR \-\-inspect \fI[=host:port]\fR
+.BR \-\-inspect \fI[=[host:]port]\fR
 Activate inspector on host:port. Default is 127.0.0.1:9229.
 
 V8 Inspector integration allows attaching Chrome DevTools and IDEs to Node.js
 instances for debugging and profiling. It uses the Chrome Debugging Protocol.
 
 .TP
-.BR \-\-inspect-brk \fI[=host:port]\fR
+.BR \-\-inspect-brk \fI[=[host:]port]\fR
 Activate inspector on host:port and break at start of user script.
 
 .TP

src/node.cc

@@ -3541,9 +3541,10 @@ static void PrintHelp() {
          "  -r, --require              module to preload (option can be "
          "repeated)\n"
 #if HAVE_INSPECTOR
-         "  --inspect[=host:port]      activate inspector on host:port\n"
+         "  --inspect[=[host:]port]    activate inspector on host:port\n"
          "                             (default: 127.0.0.1:9229)\n"
-         "  --inspect-brk[=host:port]  activate inspector on host:port\n"
+         "  --inspect-brk[=[host:]port]\n"
+         "                             activate inspector on host:port\n"
          "                             and break at start of user script\n"
 #endif
          "  --no-deprecation           silence deprecation warnings\n"