fix(DOC-1940): clarify rpk topic consume keeps connection open

modules/reference/pages/rpk/rpk-topic/rpk-topic-consume.adoc

@@ -7,8 +7,7 @@ Consuming records reads from any amount of input topics, formats each record
 according to `--format`, and prints them to `STDOUT`. The output formatter
 understands a wide variety of formats.
 
-The default output format `--format json` is a special format that outputs each
-record as JSON.
+`--format json` is the default, and outputs each record as a JSON object.
 
 include::reference:partial$topic-format.adoc[]
 
@@ -82,7 +81,7 @@ specification, similar to timestamps above.
 
 Unpacking text can allow translating binary input into readable output. If a
 value is a big-endian uint32, `%v` prints the raw four bytes, while
-`%v{unpack[>I]}` prints the number in as ASCII. If unpacking exhausts the
+`%v{unpack[>I]}` prints the number as ASCII. If unpacking exhausts the
 input before something is unpacked fully, an error message is appended to the
 output.
 
@@ -103,7 +102,7 @@ of the above rules about `%K`, `%V`, text, and numbers apply.
 
 Values for consumed records can be omitted by using the `--meta-only` flag.
 
-Tombstone records (records with a `null` value) have their value omitted from the JSON output by default. All other records, including those with an empty-string value (`""`), will have their values printed.
+Tombstone records (records with a `null` value) have their value omitted from the JSON output by default. All other records, including those with an empty-string value (`""`), have their values printed.
 
 == Offsets
 
@@ -257,4 +256,8 @@ any expression.
 |-v, --verbose |- |Enable verbose logging.
 |===
 
+== Connection behavior
+
+By default, `rpk topic consume` runs continuously, waiting for new records to arrive. It does not exit after consuming existing records. To stop consuming, press kbd:[Ctrl+C]. You can also use `--num` to exit after a fixed number of records, or use `--offset` (for example, `-o :end`) to stop at a specific offset.
+
 // end::single-source[]