Fix broken readme links, grammar, and formatting.

Author: jeaye

Diff for: README.md

@@ -126,7 +126,7 @@ convention.
 discussion in the main [Zulip installation docs][install-normal]):
 
 * `SETTINGS_EXTERNAL_HOST`: The hostname your users will use to
-  connect to your Zulip server.  If you're testing on your laptop, you
+  connect to your Zulip server.  If you're testing on your laptop,
   the default of `localhost.localdomain` is great.
 * `SETTINGS_ZULIP_ADMINISTRATOR`: The email address to receive error
   and support emails generated by the Zulip server and its users.
@@ -158,7 +158,7 @@ are secrets are set using the following syntax:
   `/etc/zulip/zulip-secrets.conf`.
 
 Reading the comments in the sample
-[Zulip's settings.py file][prod-settings-template]) is the best way to
+[Zulip's settings.py file][prod-settings-template] is the best way to
 learn about the full set of Zulip's supported server-level settings.
 
 Most settings in Zulip are just strings, but some are lists (etc.)
@@ -170,7 +170,7 @@ which you need to encode in the YAML file.  For example,
 
 **SSL Certificates**.  By default, the image will generate a
   self-signed cert.  We
-  [will soon also support certbot](https://github.com/galexrt/docker-zulip/issues/120)
+  [will soon also support certbot](https://github.com/zulip/docker-zulip/issues/120)
   for this, just like we do in normal Zulip installations
   (contributions welcome!).
 
@@ -247,13 +247,14 @@ The following are helpful examples:
 # Get a (root) shell in the container so you can access logs
 docker-compose exec zulip /bin/bash
 # Create the initial Zulip organization
-docker-compose exec zulip sudo -H -u zulip -g zulip /home/zulip/deployments/current/manage.py generate_realm_creation_link
+docker-compose exec zulip sudo -H -u zulip -g zulip \
+                          /home/zulip/deployments/current/manage.py generate_realm_creation_link
 ```
 
 Since that process for running management commands is a pain, we recommend
 [using a wrapper script][wrapper-tool] for running management commands.
 
-[wrapper-tool]: https://github.com/galexrt/docker-zulip/wiki/Running-Management-Commands
+[wrapper-tool]: https://github.com/zulip/docker-zulip/wiki/Running-Management-Commands
 
 ## Running a Zulip server with Kubernetes
 
@@ -302,7 +303,7 @@ Zulip container behind an HTTP proxy.
 [This wiki page][proxy-wiki-page] documents how to do this correctly
 with `nginx`.
 
-[proxy-wiki-page]: https://github.com/galexrt/docker-zulip/wiki/Proxying-via-nginx-on-host-machine
+[proxy-wiki-page]: https://github.com/zulip/docker-zulip/wiki/Proxying-via-nginx-on-host-machine
 
 ## Upgrading the Zulip container