Minor documentation cleanup (#7826)

* clarify link

* Add section headers

* console blocks

* grpc example json was not valid

* multi-tls update text

The preceding point 1 related to 4f2cb51ef8/ingress/controllers/nginx/examples/ingress.yaml
and the deployments referenced in 4f2cb51ef8/ingress/controllers/nginx/examples/README.md

They are not relevant to the current instructions.

* add whitespace around parens

* grammar

setup would be a proper noun, but it is not the intended concept, which is a state

* grammar

* is-only
* via

* Use bullets for choices

* ingress-controller

nginx is a distinct brand.

generally this repo talks about ingress-controller, although it is quite inconsistent about how...

* drop stray paren

* OAuth is a brand and needs an article here

also GitHub is a brand

* Indent text under numbered lists

* use e.g.

* Document that customer header config maps changes do not trigger updates

This should be removed if
https://github.com/kubernetes/ingress-nginx/issues/5238
is fixed.

* article

* period

* infinitive verb + period

* clarify that the gRPC server is responsible for listening for TCP traffic and not some other part of the backend application

* avoid using ; and reword

* whitespace

* brand: gRPC

* only-does is the right form

`for` adds nothing here

* spelling: GitHub

* punctuation

`;` is generally not the right punctuation...

* drop stray `to`

* sentence

* backticks

* fix link

* Improve readability of compare/vs

* Renumber list

* punctuation

* Favor Ingress-NGINX and Ingress NGINX

* Simplify custom header restart text

* Undo typo damage

Co-authored-by: Josh Soref <jsoref@users.noreply.github.com>

docs/examples/customization/configuration-snippets/README.md

@@ -2,13 +2,16 @@
 
 ## Ingress
 
-The Ingress in [this example](ingress.yaml) adds a custom header to Nginx configuration that only applies to that specific Ingress. If you want to add headers that apply globally to all Ingresses, please have a look at [this example](../custom-headers/README.md).
+The Ingress in [this example](ingress.yaml) adds a custom header to Nginx configuration that only applies to that specific Ingress. If you want to add headers that apply globally to all Ingresses, please have a look at [an example of specifying customer headers](../custom-headers/README.md).
 
 ```console
-$ kubectl apply -f ingress.yaml
+kubectl apply -f ingress.yaml
 ```
 
 ## Test
 
 Check if the contents of the annotation are present in the nginx.conf file using:
-`kubectl exec ingress-nginx-controller-873061567-4n3k2 -n kube-system -- cat /etc/nginx/nginx.conf`
+
+```console
+kubectl exec ingress-nginx-controller-873061567-4n3k2 -n kube-system -- cat /etc/nginx/nginx.conf
+```

docs/examples/customization/custom-headers/README.md

@@ -1,5 +1,15 @@
 # Custom Headers
 
+## Caveats
+
+Changes to the custom header config maps do not force a reload of the ingress-nginx-controllers.
+
+### Workaround
+
+To work around this limitation, perform a rolling restart of the deployment.
+
+## Example
+
 This example demonstrates configuration of the nginx ingress controller via
 a ConfigMap to pass a custom list of headers to the upstream
 server.
@@ -29,4 +39,4 @@ kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/main
 ## Test
 
 Check the contents of the ConfigMaps are present in the nginx.conf file using:
-`kubectl exec ingress-nginx-controller-873061567-4n3k2 -n ingress-nginx -- cat /etc/nginx/nginx.conf`
+`kubectl exec ingress-nginx-controller-873061567-4n3k2 -n ingress-nginx -- cat /etc/nginx/nginx.conf`

docs/examples/customization/external-auth-headers/README.md

@@ -1,7 +1,7 @@
 # External authentication, authentication service response headers propagation
 
 This example demonstrates propagation of selected authentication service response headers
-to backend service.
+to a backend service.
 
 Sample configuration includes:
 
@@ -37,7 +37,7 @@ public-demo-echo-service   public-demo-echo-service.kube.local             80
 secure-demo-echo-service   secure-demo-echo-service.kube.local             80        1m
 ```
 
-Test 1: public service with no auth header
+## Test 1: public service with no auth header
 
 ```console
 $ curl -H 'Host: public-demo-echo-service.kube.local' -v 192.168.99.100
@@ -60,7 +60,7 @@ $ curl -H 'Host: public-demo-echo-service.kube.local' -v 192.168.99.100
 UserID: , UserRole:
 ```
 
-Test 2: secure service with no auth header
+## Test 2: secure service with no auth header
 
 ```console
 $ curl -H 'Host: secure-demo-echo-service.kube.local' -v 192.168.99.100
@@ -89,7 +89,7 @@ $ curl -H 'Host: secure-demo-echo-service.kube.local' -v 192.168.99.100
 * Connection #0 to host 192.168.99.100 left intact
 ```
 
-Test 3: public service with valid auth header
+## Test 3: public service with valid auth header
 
 ```console
 $ curl -H 'Host: public-demo-echo-service.kube.local' -H 'User:internal' -v 192.168.99.100
@@ -113,7 +113,7 @@ $ curl -H 'Host: public-demo-echo-service.kube.local' -H 'User:internal' -v 192.
 UserID: 1443635317331776148, UserRole: admin
 ```
 
-Test 4: secure service with valid auth header
+## Test 4: secure service with valid auth header
 
 ```console
 $ curl -H 'Host: secure-demo-echo-service.kube.local' -H 'User:internal' -v 192.168.99.100

docs/examples/customization/ssl-dh-param/README.md

@@ -1,7 +1,7 @@
 # Custom DH parameters for perfect forward secrecy
 
 This example aims to demonstrate the deployment of an nginx ingress controller and
-use a ConfigMap to configure custom Diffie-Hellman parameters file to help with
+use a ConfigMap to configure a custom Diffie-Hellman parameters file to help with
 "Perfect Forward Secrecy".
 
 ## Custom configuration
@@ -27,7 +27,7 @@ $ kubectl create -f configmap.yaml
 ## Custom DH parameters secret
 
 ```console
-$> openssl dhparam 4096 2> /dev/null | base64
+$ openssl dhparam 4096 2> /dev/null | base64
 LS0tLS1CRUdJTiBESCBQQVJBTUVURVJ...
 ```
 
@@ -52,4 +52,6 @@ $ kubectl create -f ssl-dh-param.yaml
 ## Test
 
 Check the contents of the configmap is present in the nginx.conf file using:
-`kubectl exec ingress-nginx-controller-873061567-4n3k2 -n kube-system -- cat /etc/nginx/nginx.conf`
+```console
+$ kubectl exec ingress-nginx-controller-873061567-4n3k2 -n kube-system -- cat /etc/nginx/nginx.conf
+```

docs/examples/customization/sysctl/README.md

@@ -1,6 +1,6 @@
 # Sysctl tuning
 
-This example aims to demonstrate the use of an Init Container to adjust sysctl default values using `kubectl patch`
+This example aims to demonstrate the use of an Init Container to adjust sysctl default values using `kubectl patch`.
 
 ```console
 kubectl patch deployment -n ingress-nginx ingress-nginx-controller \