Read BJData ND-arrays of float16, restrict ND-array char to 0..127, correct BJData docs (#5931)

* Read ND-arrays of half floats and enforce the char limit in ND-arrays

BJData N-dimensional arrays with element type 'h' (float16) failed to
read with a misleading parse_error.112, because the reader's dtype name
table lacked 'h'. It now maps to "half", the JData name. The writer still
does not pack "half"; such an object is written as a plain object and
reads back equal.

BJData limits 'C' (char) to 0..127 in Draft 2 and Draft 3, and the 1-D
reader enforces this, but ND-arrays with _ArrayType_ "char" wrote values
up to 255 as 'C' elements and read them back without a check. The writer
now only packs values in 0..127 (others fall back to a plain object that
round-trips), and the reader rejects 'C' elements above 127 with
parse_error.113 like the 1-D reader.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* docs: correct and complete the BJData documentation

Verify the BJData chapter against the library and the Draft 2/3/4
specifications and fix what did not match:

- bjdata.md: correct the list of unused markers (N, not Z), the ND-array
  example (3x2, not 2x3), the conditions under which an object is packed
  as an ND-array (exactly three keys, row vectors, float-only elements for
  single/double, char 0..127, byte only in Draft 3), the binary table row
  and notes (which flag/draft combinations write [$B), the "$" type
  restriction (Draft 3, Z is excluded too), the H marker in the
  deserialization table, and the claim of a complete deserialization
  mapping. Document the supported drafts, that Draft 4 (SoA containers,
  extension type E) and column-major ND-arrays are rejected, ND-arrays of
  half floats, duplicate object keys, and link the Draft 3 specifications
  instead of master.
- Add an API page for basic_json::bjdata_version_t with an example, and
  link it from the nav, the API index and to_bjdata.
- Update binary_formats/index.md and binary_values.md, which still claimed
  that BJData has no binary type, and fix a wrong byte comment there.
- Document parse_error.115 and the out_of_range.408 cases for from_bjdata,
  the precise other_error.502 condition for to_bjdata, and reword the note
  on truncated unsigned integers in exceptions.md (only ND-array elements
  were truncated before 3.13.0).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate single_include and apply astyle

Result of make amalgamate (including make pretty) for the preceding changes.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address review of the BJData documentation

The $ type restriction exists since Draft 2 (Draft 3 added B), $ requires a count, ND char above 127 is rejected on read, and the new API page is listed in alphabetical order in the nav.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* docs: format tables, use the Oxford comma

Reformat the tables changed by this PR (BJData serialization and
deserialization mappings, completeness and binary-value tables) so all
rows are aligned, and add the Oxford comma to lists of three or more
items in the added text.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

docs/mkdocs/docs/features/binary_values.md

@@ -132,8 +132,11 @@ is an integer or `null`.
 
 ### BJData
 
-[BJData](binary_formats/bjdata.md) neither supports binary values nor subtypes and proposes to serialize binary values
-as an array of uint8 values. The library implements this translation.
+[BJData](binary_formats/bjdata.md) Draft 3 supports binary values as optimized arrays of `B` (byte) elements, but no
+subtypes. With `version = bjdata_version_t::draft3` and both `use_size` and `use_type` set, `to_bjdata` writes a binary
+value as `[$B#...`, and `from_bjdata` reads it back as a binary value (without subtype). In all other cases, including
+the default Draft 2 mode, the library follows the Draft 2 proposal and writes an array of integers (`U` in Draft 2, `B`
+in Draft 3), which is read back as an array.
 
 ??? example "Example: serialize a binary value to BJData"
 
@@ -171,7 +174,7 @@ as an array of uint8 values. The library implements this translation.
 
     ```c
     0x7B                                // '{'
-        0x23 0x69 0x01                  // '#' 'i' type of the array elements: unsigned integers
+        0x23 0x69 0x01                  // '#' 'i' 1 number of object members
         0x69 0x06                       // i 6 (length of the key)
         0x62 0x69 0x6E 0x61 0x72 0x79   // "binary"
         0x5B                            // '[' array
@@ -180,7 +183,7 @@ as an array of uint8 values. The library implements this translation.
             0xCA 0xFE 0xBA 0xBE         // content
     ```
 
-    Note that subtype (42) is **not** serialized and that BJData has **no binary type**, and deserializing `v` would
+    Note that subtype (42) is **not** serialized and that, in Draft 2 mode, BJData has **no binary type**, and deserializing `v` would
     yield the following value:
 
     ```json