Replace "function" with "command" in several user-facing doc (#15129)

crates/nu-std/std/formats/mod.nu

@@ -1,40 +1,40 @@
 # formats.nu
 #
-# This file contains functions for formatting data in various ways.
+# This file contains helpers for formatting data in various ways.
 #
 # Usage:
-#   use std format *
-#   use std format <function name>
+#   use std/format *
+#   use std/format <command name>
 #
-# These functions help `open` the files with unsupported extensions such as ndjson.
+# These custom commands help `open` the files with unsupported extensions such as ndjson.
 #
 
-# Convert from [NDJSON](https://github.com/ndjson/ndjson-spec) to structured data.
+# Convert from NDJSON (https://github.com/ndjson/ndjson-spec) to structured data.
 export def "from ndjson" []: string -> any {
     from json --objects
 }
 
-# Convert from [JSONL](https://jsonlines.org/) to structured data.
+# Convert from JSONL (https://jsonlines.org/) to structured data.
 export def "from jsonl" []: string -> any {
     from json --objects
 }
 
-# Convert structured data to [NDJSON](https://github.com/ndjson/ndjson-spec).
+# Convert structured data to NDJSON (https://github.com/ndjson/ndjson-spec).
 export def "to ndjson" []: any -> string {
     each { to json --raw } | to text
 }
 
-# Convert structured data to [JSONL](https://jsonlines.org/).
+# Convert structured data to JSONL (https://jsonlines.org/).
 export def "to jsonl" []: any -> string {
     each { to json --raw } | to text
 }
 
-# Convert from NDNUON (newline-delimited NUON), to structured data
+# Convert from NDNUON (newline-delimited NUON) to structured data
 export def "from ndnuon" []: [string -> any] {
     lines | each { from nuon }
 }
 
-# Convert structured data to NDNUON, i.e. newline-delimited NUON
+# Convert structured data to newline-delimited NUON (NDNUON)
 export def "to ndnuon" []: [any -> string] {
     each { to nuon --raw | str replace --all "\n" '\n' } | to text
 }