Declare xml.colors settings

See eclipse-lemminx/lemminx#639

Signed-off-by: azerr <azerr@redhat.com>

README.md

@@ -20,6 +20,7 @@ This VS Code extension provides support for creating and editing XML documents,
 | enabled by default | requires additional configuration to enable |
 
 - * [XML References features](https://github.com/redhat-developer/vscode-xml/blob/main/docs/Features/XMLReferencesFeatures.md#xml-references-features) (since v0.24.0)
+- * [XML Colors features](https://github.com/redhat-developer/vscode-xml/blob/main/docs/Features/XMLColorsFeatures.md#xml-colors-features) (since v0.24.0)
   * [RelaxNG (experimental) support](https://github.com/redhat-developer/vscode-xml/blob/main/docs/Features/RelaxNGFeatures.md#relaxng-features) (since v0.22.0)
   * [Surround with Tags, Comments, CDATA](https://github.com/redhat-developer/vscode-xml/blob/main/docs/Refactor.md#refactor) (since v0.23.0)
   * Syntax error reporting

docs/Features.md

@@ -8,4 +8,5 @@
 - [RelaxNG features](Features/RelaxNGFeatures.md#relaxng-features)
 - [XInclude features](Features/XIncludeFeatures.md#xinclude-features)
 - [XML Catalog features](Features/XMLCatalogFeatures.md#xml-catalog-features)
-- [XML References features](Features/XMLReferencesFeatures.md#xml-references-features)
+- [XML References features](Features/XMLReferencesFeatures.md#xml-references-features)
+- [XML Colors features](Features/XMLReferencesFeatures.md#xml-colors-features)

docs/Features/XMLColorsFeatures.md

@@ -0,0 +1,66 @@
+# XML Colors Features
+
+XML colors support provides the capability to mark a DOM node (attribute or text) as color with the `xml.colors` settings by using XPath expression : 
+
+ * `color/text()` defines the text node of the `color` element.
+ * `item/@color` defines the `color` attribute node of the `item` element.
+
+## Text node color (color/text())
+
+Given this [android color](https://developer.android.com/guide/topics/resources/more-resources#Color) XML file sample:
+
+```xml
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+	<color name="opaque_red">#f00</color>
+	<color name="translucent_red">rgb(222,82,0.82)</color>
+</resources>
+```
+
+In this sample, text of `color` tag element `<color name="opaque_red">#f00</color>` declare a color with hexadecimal. [vscode-xml](https://github.com/redhat-developer/vscode-xml) provides a color support with the `xml.colors` settings. For [android color](https://developer.android.com/guide/topics/resources/more-resources#Color) case, you can declare this settings:
+
+```json
+"xml.colors": [
+   {
+      "pattern": "**/res/values/colors.xml",
+      "expressions": [
+         {
+            "xpath": "resources/color/text()"
+         }
+      ]
+   }
+]
+```
+
+After saving this setting, you will get color support for text noe of `color` in the colors.xml file:
+
+![XML Colors](../images/Features/XMLColorsFeatures.png)
+
+## Attribute node color (item/@color)
+
+It is possible too to mark attribute as color, by using the proper XPath.
+
+Given this `colors.xml` XML file:
+
+```xml
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+	<item color="#f00" />
+	<item color="rgb(222,82,0.82)" />
+</resources>
+```
+
+You can declare this settings:
+
+```json
+"xml.colors": [
+   {
+      "pattern": "**/colors.xml",
+      "expressions": [
+         {
+            "xpath": "item/@color"
+         }
+      ]
+   }
+]
+```

docs/Features/XMLReferencesFeatures.md

@@ -1,6 +1,6 @@
 # XML References Features
 
-XML References support provides the capability to reference a DOM node (attribute or text) to an another DOM node (attribute or text) with a the `xml.references` settings by using XPath expression : 
+XML References support provides the capability to reference a DOM node (attribute or text) to an another DOM node (attribute or text) with the `xml.references` settings by using XPath expression : 
 
  * `foo/@attr` defines the `attr` attribute node of the `foo` element.
  * `foo/text()` defines the text node of the `foo` element.

package.json

@@ -674,7 +674,42 @@
               "expressions"
             ]
           },
-          "markdownDescription": "Allows XML schemas/ DTD to be associated to file name patterns. Please refer to [XML file association with XSD](command:xml.open.docs?%5B%7B%22page%22%3A%22Validation%22%2C%22section%22%3A%22xml-file-association-with-xsd%22%7D%5D) or [XML file association with DTD](command:xml.open.docs?%5B%7B%22page%22%3A%22Validation%22%2C%22section%22%3A%22xml-file-association-with-dtd%22%7D%5D) for more information. \n\nExample:\n```json\n[{\n  \"pattern\": \"file1.xml\",\n  \"systemId\": \"path/to/file.xsd\"\n},\n{\n  \"pattern\": \"**/*.xsd\",\n  \"systemId\": \"http://www.w3.org/2001/XMLSchema.xsd\"\n}]\n```",
+          "markdownDescription": "Allows references for the given file name patterns.",
+          "scope": "window"
+        },
+        "xml.colors": {
+          "type": "array",
+          "default": [],
+          "items": {
+            "type": "object",
+            "properties": {
+              "pattern": {
+                "type": "string",
+                "markdownDescription": "matches the files that colors declared with `expressions` applies to.\n\nMore information on the glob syntax: https://docs.oracle.com/javase/tutorial/essential/io/fileOps.html#glob"
+              },
+              "expressions": {
+                "type": "array",
+                "default": [],
+                "items": {
+                  "type": "object",
+                  "properties": {
+                    "xpath": {
+                      "type": "string",
+                      "description": "The color DOM node (attribute, text) declared with XPath (ex: foo/@color, foo/text())"
+                    }
+                  }
+                },
+                "required": [
+                  "xpath"
+                ]
+              }
+            },
+            "required": [
+              "pattern",
+              "expressions"
+            ]
+          },
+          "markdownDescription": "Allows colors for the given file name patterns.",
           "scope": "window"
         },
         "xml.extension.jars": {