doc: add missing env variables to man page

This commit adds the missing environment variables
NODE_DEBUG_NATIVE, NODE_PRESERVE_SYMLINKS,
NODE_TLS_REJECT_UNAUTHORIZED, NODE_V8_COVERAGE, and
UV_THREADPOOL_SIZE to the man page.

PR-URL: #24383
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ouyang Yadong <oyydoibh@gmail.com>
Reviewed-By: Weijia Wang <starkwang@126.com>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

doc/node.1

@@ -278,6 +278,9 @@ Print node's version.
 .It Ev NODE_DEBUG Ar modules...
 Comma-separated list of core modules that should print debug information.
 .
+.It Ev NODE_DEBUG_NATIVE Ar modules...
+Comma-separated list of C++ core modules that should print debug information.
+.
 .It Ev NODE_DISABLE_COLORS
 When set to
 .Ar 1 ,
@@ -326,6 +329,11 @@ When set to
 .Ar 1 ,
 emit pending deprecation warnings.
 .
+.It Ev NODE_PRESERVE_SYMLINKS
+When set to
+.Ar 1 ,
+the module loader preserves symbolic links when resolving and caching modules.
+.
 .It Ev NODE_REDIRECT_WARNINGS Ar file
 Write process warnings to the given
 .Ar file
@@ -342,6 +350,15 @@ The default path is
 which is overridden by this variable.
 Setting the value to an empty string ("" or " ") will disable persistent REPL history.
 .
+.It Ev NODE_TLS_REJECT_UNAUTHORIZED
+When set to
+.Ar 0 ,
+TLS certificate validation is disabled.
+.
+.It Ev NODE_V8_COVERAGE Ar dir
+When set, Node.js writes JavaScript code coverage information to
+.Ar dir .
+.
 .It Ev OPENSSL_CONF Ar file
 Load an OpenSSL configuration file on startup.
 Among other uses, this can be used to enable FIPS-compliant crypto if Node.js is built with
@@ -360,8 +377,12 @@ is enabled, this overrides and sets OpenSSL's directory containing trusted certi
 If
 .Fl -use-openssl-ca
 is enabled, this overrides and sets OpenSSL's file containing trusted certificates.
-.El
 .
+.It Ev UV_THREADPOOL_SIZE Ar size
+Sets the number of threads used in libuv's threadpool to
+.Ar size .
+.
+.El
 .\"=====================================================================
 .Sh BUGS
 Bugs are tracked in GitHub Issues: