doc: fix grammar in global dispatcher usage · nodejs/node@8341916

nodejs

Original file line number	Diff line number	Diff line change
@@ -537,7 +537,7 @@ The dispatcher must be compatible with `undici`'s
`537`	`537`	`fetch(url, { dispatcher: new MyAgent() });`
`538`	`538`	```
`539`	`539`
`540`		-It is possible to change the global dispatcher in Node.js installing `undici` and using
	`540`	+It is possible to change the global dispatcher in Node.js by installing `undici` and using
`541`	`541`	the `setGlobalDispatcher()` method. Calling this method will affect both `undici` and
`542`	`542`	`Node.js.`
`543`	`543`