docs: describe the difference between configuration fields and runtim…

…e flags (vectordotdev#17784)

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This PR adds docs describing a detail of our UX system around CLI args 😎

STYLE.md

@@ -327,3 +327,22 @@ you'll need to use an asynchronous-specific synchronization primitives, namely t
 itself. The documentation on `tokio`'s own
 [`Mutex`](https://docs.rs/tokio/latest/tokio/sync/struct.Mutex.html), for example, calls out the
 specifics of when and where you might need to use it vs the one from `std::sync`.
+
+
+## New Configuration Fields vs CLI flags
+
+Vector makes the distinction between configuration items that are essential to understand data
+pipelines and runtime flags that determine the details of the runtime behavior. The main configuration
+generally lives in a file in the current directory or in `/etc/vector`.
+
+Examples of main configuration fields are source, transformation, and sink declaration, as well as
+information about where any disk buffers should be persisted.
+
+For configuration items that purely inform details of Vector's runtime behavior, CLI flags without
+corresponding configuration fields should be used.
+
+An example of a runtime flag is
+`vector run --no-graceful-shutdown-limit`, which tells Vector to ignore SIGINTs and to continue running
+as normal until a SIGKILL is received. In this case, as the configuration describes the desired runtime
+behavior in a specific environment and not to the underlying data pipeline, no corresponding field in
+the configuration file should exist.