crypto/x509: move and update the SSL_CERT_FILE and SSL_CERT_DIR docs

Fixes #37907

Change-Id: Ia077de6dcc74ed761d278eab4efbf45e151429b8
Reviewed-on: https://go-review.googlesource.com/c/go/+/239747
Run-TryBot: Filippo Valsorda <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>
Reviewed-by: Katie Hockman <[email protected]>

Author: FiloSottile

src/crypto/x509/cert_pool.go

@@ -47,11 +47,15 @@ func (s *CertPool) copy() *CertPool {
 
 // SystemCertPool returns a copy of the system cert pool.
 //
-// Any mutations to the returned pool are not written to disk and do
-// not affect any other pool returned by SystemCertPool.
+// On Unix systems other than macOS the environment variables SSL_CERT_FILE and
+// SSL_CERT_DIR can be used to override the system default locations for the SSL
+// certificate file and SSL certificate files directory, respectively. The
+// latter can be a colon-separated list.
 //
-// New changes in the system cert pool might not be reflected
-// in subsequent calls.
+// Any mutations to the returned pool are not written to disk and do not affect
+// any other pool returned by SystemCertPool.
+//
+// New changes in the system cert pool might not be reflected in subsequent calls.
 func SystemCertPool() (*CertPool, error) {
 	if runtime.GOOS == "windows" {
 		// Issue 16736, 18609:

src/crypto/x509/x509.go

@@ -3,10 +3,6 @@
 // license that can be found in the LICENSE file.
 
 // Package x509 parses X.509-encoded keys and certificates.
-//
-// On UNIX systems the environment variables SSL_CERT_FILE and SSL_CERT_DIR
-// can be used to override the system default locations for the SSL certificate
-// file and SSL certificate files directory, respectively.
 package x509
 
 import (