Repetition of optional variables in custom scripts

Merge the repeated sentences to the second instance.

docs/additional-features/custom-scripts.md

@@ -19,7 +19,7 @@ class MyScript(Script):
     ...
 ```
 
-Scripts comprise two core components: a set of variables and a `run()` method. Variables allow your script to accept user input via the NetBox UI, but they are optional: If your script does not require any user input, there is no need to define any variables.
+Scripts comprise two core components: a set of variables and a `run()` method.
 
 The `run()` method is where your script's execution logic lives. (Note that your script can have as many methods as needed: this is merely the point of invocation for NetBox.)
 
@@ -41,7 +41,7 @@ The `run()` method should accept two arguments:
 !!! note
     The `commit` argument was introduced in NetBox v2.7.8. Backward compatibility is maintained for scripts which accept only the `data` argument, however beginning with v2.10 NetBox will require the `run()` method of every script to accept both arguments. (Either argument may still be ignored within the method.)
 
-Defining script variables is optional: You may create a script with only a `run()` method if no user input is needed.
+Variables allow your script to accept user input via the NetBox UI, but they are optional: If your script does not require any user input, there is no need to define any variables and you may create a script with only a `run()` method.
 
 Any output generated by the script during its execution will be displayed under the "output" tab in the UI.