Fix md generation for kubectl docs

Display usage string, not long help, as code, remove angle brackets from
output (.md interprets as tags and hides).

docs/kubectl-create.md

@@ -4,13 +4,14 @@ Create a resource by filename or stdin
 
 ### Synopsis
 
-```
+
 Create a resource by filename or stdin.
 
 JSON and YAML formats are accepted.
-```
 
-kubectl create -f filename
+```
+kubectl create -f FILENAME
+```
 
 ### Examples