docs: Update dev-env-first-time-contributors doc.

docs/dev-env-first-time-contributors.md

@@ -719,7 +719,7 @@ If you receive the following error while running `vagrant up`:
 SSL read: error:00000000:lib(0):func(0):reason(0), errno 104
 ```
 
-It means that either your network connection is unstable or speed 
+It means that either your network connection is unstable or speed
 is very less. It can simply be resolved by executing the same command i.e
 `vagrant up` when your network connection gets stable.
 
@@ -902,12 +902,12 @@ If you receive the following error after running `./tools/provision`:
 ```
 An unexpected error occurred: "https://registry.yarnpkg.com/typescript/-/typescript-2.3.3.tgz: ESOCKETTIMEDOUT".
 
-Error running a subcommand of ./lib/provision.py: 
-/srv/zulip/scripts/lib/cd_exec /srv/zulip-npm-cache/78ff765baf4566250680b34be446d85b7ec6f5d7 
+Error running a subcommand of ./lib/provision.py:
+/srv/zulip/scripts/lib/cd_exec /srv/zulip-npm-cache/78ff765baf4566250680b34be446d85b7ec6f5d7
 /srv/zulip-yarn/bin/yarn install --non-interactive
 ```
 
-It is likely due to the poor internet connection or unstable network. 
+It is likely due to the poor internet connection or unstable network.
 When your network connection gets stable you can proceed by re-running the same command:
 `./tools/provision`, and then your zulip server will start.