doc: remove redundant warning information

process.emitWarning() already describes how to emit custom warnings,
so just merely provide a link to that function from the 'warning'
event documentation.

PR-URL: #9590
Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed-By: Prince John Wesley <princejohnwesley@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

doc/api/process.md

@@ -312,50 +312,6 @@ $ node --no-warnings
 The `--trace-warnings` command-line option can be used to have the default
 console output for warnings include the full stack trace of the warning.
 
-#### Emitting custom warnings
-
-The [`process.emitWarning()`][process_emit_warning] method can be used to issue
-custom or application specific warnings.
-
-```js
-// Emit a warning using a string...
-process.emitWarning('Something happened!');
-  // Prints: (node 12345) Warning: Something happened!
-
-// Emit a warning using an object...
-process.emitWarning('Something Happened!', 'CustomWarning');
-  // Prints: (node 12345) CustomWarning: Something happened!
-
-// Emit a warning using a custom Error object...
-class CustomWarning extends Error {
-  constructor(message) {
-    super(message);
-    this.name = 'CustomWarning';
-    Error.captureStackTrace(this, CustomWarning);
-  }
-}
-const myWarning = new CustomWarning('Something happened!');
-process.emitWarning(myWarning);
-  // Prints: (node 12345) CustomWarning: Something happened!
-```
-
-#### Emitting custom deprecation warnings
-
-Custom deprecation warnings can be emitted by setting the `name` of a custom
-warning to `DeprecationWarning`. For instance:
-
-```js
-process.emitWarning('This API is deprecated', 'DeprecationWarning');
-```
-
-Or,
-
-```js
-const err = new Error('This API is deprecated');
-err.name = 'DeprecationWarning';
-process.emitWarning(err);
-```
-
 Launching Node.js using the `--throw-deprecation` command line flag will
 cause custom deprecation warnings to be thrown as exceptions.
 
@@ -368,6 +324,11 @@ of the custom deprecation.
 The `*-deprecation` command line flags only affect warnings that use the name
 `DeprecationWarning`.
 
+#### Emitting custom warnings
+
+See the [`process.emitWarning()`][process_emit_warning] method for issuing
+custom or application-specific warnings.
+
 ### Signal Events
 
 <!--type=event-->