Add plugin types (#1527)

Covered following plugins
- addAttributesToSVGElement.js 
- addClassesToSVGElement.js 
- cleanupAttrs.js 
- convertEllipseToCircle.js 
- removeAttributesBySelector.js 
- removeAttrs.js 
- removeComments.js 
- removeDesc.js 
- removeDoctype.js 
- removeElementsByAttr.js 
- removeEmptyText.js 
- removeMetadata.js 
- removeRasterImages.js 
- removeScriptElement.js 
- removeStyleElement.js 
- removeTitle.js 
- removeXMLProcInst.js

plugins/removeElementsByAttr.js

@@ -11,9 +11,7 @@ exports.description =
 /**
  * Remove arbitrary SVG elements by ID or className.
  *
- * @param id
- *   examples:
- *
+ * @example id
  *     > single: remove element with ID of `elementID`
  *     ---
  *     removeElementsByAttr:
@@ -26,9 +24,7 @@ exports.description =
  *         - 'elementID'
  *         - 'anotherID'
  *
- * @param class
- *   examples:
- *
+ * @example class
  *     > single: remove all elements with class of `elementClass`
  *     ---
  *     removeElementsByAttr:
@@ -42,6 +38,11 @@ exports.description =
  *         - 'anotherClass'
  *
  * @author Eli Dupuis (@elidupuis)
+ *
+ * @type {import('../lib/types').Plugin<{
+ *   id?: string | Array<string>,
+ *   class?: string | Array<string>
+ * }>}
  */
 exports.fn = (root, params) => {
   const ids =