to <format>: preserve round float numbers' type (#16016)

- fixes #16011

# Description
`Display` implementation for `f64` omits the decimal part for round
numbers, and by using it we did the same.
This affected:
- conversions to delimited formats: `csv`, `tsv`
- textual formats: `html`, `md`, `text`
- pretty printed `json` (`--raw` was unaffected)
- how single float values are displayed in the REPL

> [!TIP]
> This PR fixes our existing json pretty printing implementation.
> We can likely switch to using serde_json's impl using its
PrettyFormatter which allows arbitrary indent strings.

# User-Facing Changes
- Round trips through `csv`, `tsv`, and `json` preserve the type of
round floats.
- It's always clear whether a number is an integer or a float in the
REPL
  ```nushell
  4 / 2
  # => 2  # before: is this an int or a float?

  4 / 2
  # => 2.0  # after: clearly a float
  ``` 

# Tests + Formatting
Adjusted tests for the new behavior.

- 🟢 toolkit fmt
- 🟢 toolkit clippy
- 🟢 toolkit test
- 🟢 toolkit test stdlib

# After Submitting
N/A

---------

Co-authored-by: Bahex <17417311+Bahex@users.noreply.github.com>

crates/nu-command/tests/commands/database/query_db.rs

@@ -68,7 +68,7 @@ fn ordered_params() {
 
         assert_eq!(
             results.out,
-            "nimurod-20-6-1-2024-03-23 00:15:24-03:00-72400000-1000000--[104, 101, 108, 108, 111]_\
+            "nimurod-20-6.0-1-2024-03-23 00:15:24-03:00-72400000-1000000--[104, 101, 108, 108, 111]_\
             string-int-float-int-string-int-int-nothing-binary"
         );
     });
@@ -108,7 +108,7 @@ fn named_params() {
 
         assert_eq!(
             results.out,
-            "nimurod-20-6-1-2024-03-23 00:15:24-03:00-72400000-1000000--[104, 101, 108, 108, 111]_\
+            "nimurod-20-6.0-1-2024-03-23 00:15:24-03:00-72400000-1000000--[104, 101, 108, 108, 111]_\
             string-int-float-int-string-int-int-nothing-binary"
         );
     });