feat(removeDeprecatedAttrs): new removeDeprecatedAttrs plugin

The new removeDeprecatedAttributes removes deprecated attributes from
the SVG document that have no effect on rendering. For example, the
"version" attribute on the "svg" element is deprecated and not
recommended as documented on MDN:

https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/version

> Deprecated: This feature is no longer recommended. Though some
> browsers might still support it, it may have already been removed from
> the relevant web standards, may be in the process of being dropped, or
> may only be kept for compatibility purposes. Avoid using it, and
> update existing code if possible; see the compatibility table at the
> bottom of this page to guide your decision. Be aware that this feature
> may cease to work at any time.

The document:

```
<svg version="1.1" viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg">
  <rect x="10" y="10" width="80" height="80"/>
</svg>
```

Becomes:

```
<svg viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg">
  <rect x="10" y="10" width="80" height="80"/>
</svg>
```

The plugin is built for easy expansion as new deprecated attributes are
discovered or announced. Simply add a "deprecated" key to the elems data
structure in plugins/_collections.js.

Fixes #1701

docs/02-preset-default.mdx

@@ -41,6 +41,7 @@ The following plugins are included in `preset-default`, in the order that they'r
 * [Collapse Groups](/docs/plugins/collapse-groups/)
 * [Convert Path Data](/docs/plugins/convert-path-data/)
 * [Convert Transform](/docs/plugins/convert-transform/)
+* [Remove Deprecated Attributes](/docs/plugins/remove-deprecated-attrs/)
 * [Remove Empty Attributes](/docs/plugins/remove-empty-attrs/)
 * [Remove Empty Containers](/docs/plugins/remove-empty-containers/)
 * [Remove Unused Namespaces](/docs/plugins/remove-unused-namespaces/)

docs/03-plugins/remove-deprecated-attrs.mdx

@@ -0,0 +1,20 @@
+---
+title: Remove Deprecated Attributes
+svgo:
+  pluginId: removeDeprecatedAttrs
+  defaultPlugin: true
+---
+
+Remove deprecated attributes from elements in the document.
+
+## Usage
+
+<PluginUsage/>
+
+## Demo
+
+<PluginDemo/>
+
+## Implementation
+
+* https://github.com/svg/svgo/blob/main/plugins/removeDeprecatedAttrs.js

lib/builtin.js

@@ -27,6 +27,7 @@ exports.builtin = [
   require('../plugins/removeAttributesBySelector.js'),
   require('../plugins/removeAttrs.js'),
   require('../plugins/removeComments.js'),
+  require('../plugins/removeDeprecatedAttrs.js'),
   require('../plugins/removeDesc.js'),
   require('../plugins/removeDimensions.js'),
   require('../plugins/removeDoctype.js'),

plugins/_collections.js

@@ -374,6 +374,7 @@ exports.attrsGroupsDefaults = {
  *   attrsGroups: Array<string>,
  *   attrs?: Array<string>,
  *   defaults?: Record<string, string>,
+ *   deprecated?: Array<string>,
  *   contentGroups?: Array<string>,
  *   content?: Array<string>,
  * }>}
@@ -1679,6 +1680,69 @@ exports.elems = {
       contentScriptType: 'application/ecmascript',
       contentStyleType: 'text/css',
     },
+    deprecated: [
+      'accent-height',
+      'alphabetic',
+      'arabic-form',
+      'ascent',
+      'attributeType',
+      'baseProfile',
+      'bbox',
+      'cap-height',
+      'clip',
+      'color-profile',
+      'contentScriptType',
+      'contentStyleType',
+      'descent',
+      'enable-background',
+      'filterRes',
+      'g1',
+      'g2',
+      'glyph-name',
+      'glyph-orientation-horizontal',
+      'glyph-orientation-vertical',
+      'hanging',
+      'horiz-adv-x',
+      'horiz-origin-x',
+      'horiz-origin-y',
+      'ideographic',
+      'k',
+      'kerning',
+      'mathematical',
+      'name',
+      'orientation',
+      'panose-1',
+      'requiredFeatures',
+      'slope',
+      'stemh',
+      'stemv',
+      'string',
+      'u1',
+      'u2',
+      'unicode',
+      'unicode-range',
+      'units-per-em',
+      'v-alphabetic',
+      'v-hanging',
+      'v-ideographic',
+      'v-mathematical',
+      'version',
+      'vert-adv-y',
+      'vert-origin-x',
+      'vert-origin-y',
+      'viewTarget',
+      'widths',
+      'x-height',
+      'xlink:arcrole',
+      'xlink:href',
+      'xlink:show',
+      'xlink:title',
+      'xlink:type',
+      'xml:base',
+      'xml:lang',
+      'xml:space',
+      'zoomAndPan',
+    ],
     contentGroups: [
       'animation',
       'descriptive',

plugins/plugins-types.d.ts

@@ -141,6 +141,7 @@ type DefaultPlugins = {
   removeComments: {
     preservePatterns: Array<RegExp | string> | false;
   };
+  removeDeprecatedAttrs: void;
   removeDesc: {
     removeAny?: boolean;
   };

plugins/preset-default.js

@@ -15,6 +15,7 @@ const cleanupIds = require('./cleanupIds.js');
 const removeUselessDefs = require('./removeUselessDefs.js');
 const cleanupNumericValues = require('./cleanupNumericValues.js');
 const convertColors = require('./convertColors.js');
+const removeDeprecatedAttrs = require('./removeDeprecatedAttrs.js');
 const removeUnknownsAndDefaults = require('./removeUnknownsAndDefaults.js');
 const removeNonInheritableGroupAttrs = require('./removeNonInheritableGroupAttrs.js');
 const removeUselessStrokeAndFill = require('./removeUselessStrokeAndFill.js');
@@ -68,6 +69,7 @@ const presetDefault = createPreset({
     collapseGroups,
     convertPathData,
     convertTransform,
+    removeDeprecatedAttrs,
     removeEmptyAttrs,
     removeEmptyContainers,
     mergePaths,

plugins/removeDeprecatedAttrs.js

@@ -0,0 +1,29 @@
+'use strict';
+
+const { elems } = require('./_collections');
+
+exports.name = 'removeDeprecatedAttrs';
+exports.description = 'removes deprecated attributes';
+
+/**
+ * Remove deprecated attributes.
+ *
+ * @type {import('./plugins-types').Plugin<'removeDeprecatedAttrs'>}
+ */
+exports.fn = () => {
+  return {
+    element: {
+      enter: (node) => {
+        const elemConfig = elems[node.name];
+        if (elemConfig) {
+          const deprecated = elemConfig.deprecated;
+          if (deprecated) {
+            deprecated.forEach((name) => {
+              delete node.attributes[name];
+            });
+          }
+        }
+      },
+    },
+  };
+};