doc: add instructions to update local git config

this code change updates pull-requests.md to instruct developers to
update their local git config instead of global. This way their global
git config won't be overwritten if they use different email ID for work
or personal or non-Github projects

PR-URL: nodejs#19777
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/guides/contributing/pull-requests.md

@@ -62,18 +62,6 @@ These are detailed in the [Building guide][].
 Once you have `git` and are sure you have all of the necessary dependencies,
 it's time to create a fork.
 
-Before getting started, it is recommended to configure `git` so that it knows
-who you are:
-
-```text
-$ git config --global user.name "J. Random User"
-$ git config --global user.email "j.random.user@example.com"
-```
-Please make sure this local email is also added to your
-[GitHub email list](https://github.com/settings/emails) so that your commits
-will be properly associated with your account and you will be promoted
-to Contributor once your first commit is landed.
-
 ### Step 1: Fork
 
 Fork the project [on GitHub](https://github.com/nodejs/node) and clone your fork
@@ -86,6 +74,17 @@ $ git remote add upstream https://github.com/nodejs/node.git
 $ git fetch upstream
 ```
 
+It is recommended to configure `git` so that it knows who you are:
+
+```text
+$ git config user.name "J. Random User"
+$ git config user.email "j.random.user@example.com"
+```
+Please make sure this local email is also added to your
+[GitHub email list](https://github.com/settings/emails) so that your commits
+will be properly associated with your account and you will be promoted
+to Contributor once your first commit is landed.
+
 ### Step 2: Branch
 
 As a best practice to keep your development environment as organized as