Cosmetics - no code behaviour changes (#397)

* Revert ioutil deprecation commit

While go 1.16 is 2 years old, I feel like I should not go out of my way
to break the library for users on go versions lower that 1.16. This
commit reverts part of the changes from #392.

* fix some doc comments for go v1.19 rules

* Fix wrong total number of supported mimes

The mistake was introduced in a merge commit.

internal/magic/binary.go

@@ -150,32 +150,34 @@ func Marc(raw []byte, limit uint32) bool {
 }
 
 // Glb matches a glTF model format file.
-// GLB is the binary file format representation of 3D models save in
+// GLB is the binary file format representation of 3D models saved in
 // the GL transmission Format (glTF).
-// see more: https://docs.fileformat.com/3d/glb/
-//           https://www.iana.org/assignments/media-types/model/gltf-binary
-// GLB file format is based on little endian and its header structure
-// show  below:
+// GLB uses little endian and its header structure is as follows:
 //
-// <-- 12-byte header                             -->
-// | magic            | version          | length   |
-// | (uint32)         | (uint32)         | (uint32) |
-// | \x67\x6C\x54\x46 | \x01\x00\x00\x00 | ...      |
-// | g   l   T   F    | 1                | ...      |
+// 	<-- 12-byte header                             -->
+// 	| magic            | version          | length   |
+// 	| (uint32)         | (uint32)         | (uint32) |
+// 	| \x67\x6C\x54\x46 | \x01\x00\x00\x00 | ...      |
+// 	| g   l   T   F    | 1                | ...      |
+//
+// Visit [glTF specification] and [IANA glTF entry] for more details.
+//
+// [glTF specification]: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html
+// [IANA glTF entry]: https://www.iana.org/assignments/media-types/model/gltf-binary
 var Glb = prefix([]byte("\x67\x6C\x54\x46\x02\x00\x00\x00"),
 	[]byte("\x67\x6C\x54\x46\x01\x00\x00\x00"))
 
 // TzIf matches a Time Zone Information Format (TZif) file.
 // See more: https://tools.ietf.org/id/draft-murchison-tzdist-tzif-00.html#rfc.section.3
 // Its header structure is shown below:
-// +---------------+---+
-// |  magic    (4) | <-+-- version (1)
-// +---------------+---+---------------------------------------+
-// |           [unused - reserved for future use] (15)         |
-// +---------------+---------------+---------------+-----------+
-// |  isutccnt (4) |  isstdcnt (4) |  leapcnt  (4) |
-// +---------------+---------------+---------------+
-// |  timecnt  (4) |  typecnt  (4) |  charcnt  (4) |
+// 	+---------------+---+
+// 	|  magic    (4) | <-+-- version (1)
+// 	+---------------+---+---------------------------------------+
+// 	|           [unused - reserved for future use] (15)         |
+// 	+---------------+---------------+---------------+-----------+
+// 	|  isutccnt (4) |  isstdcnt (4) |  leapcnt  (4) |
+// 	+---------------+---------------+---------------+
+// 	|  timecnt  (4) |  typecnt  (4) |  charcnt  (4) |
 func TzIf(raw []byte, limit uint32) bool {
 	// File is at least 44 bytes (header size).
 	if len(raw) < 44 {

internal/magic/magic.go

@@ -177,7 +177,9 @@ func newXMLSig(localName, xmlns string) xmlSig {
 // and, optionally, followed by the arguments for the interpreter.
 //
 // Ex:
-//  #! /usr/bin/env php
+//
+//	#! /usr/bin/env php
+//
 // /usr/bin/env is the interpreter, php is the first and only argument.
 func shebang(sigs ...[]byte) Detector {
 	return func(raw []byte, limit uint32) bool {

mimetype.go

@@ -7,6 +7,7 @@ package mimetype
 
 import (
 	"io"
+	"io/ioutil"
 	"mime"
 	"os"
 	"sync/atomic"
@@ -47,7 +48,7 @@ func DetectReader(r io.Reader) (*MIME, error) {
 	// Using atomic because readLimit can be written at the same time in other goroutine.
 	l := atomic.LoadUint32(&readLimit)
 	if l == 0 {
-		in, err = io.ReadAll(r)
+		in, err = ioutil.ReadAll(r)
 		if err != nil {
 			return errMIME, err
 		}

supported_mimes.md

@@ -1,4 +1,4 @@
-## 172 Supported MIME types
+## 173 Supported MIME types
 This file is automatically generated when running tests. Do not edit manually.
 
 Extension | MIME type | Aliases