Add "commentpragma" html style rule (#5726)

* html-comment, that can be used in the pragma area

* add commentpragma test

* fix typo

* fix typo and change comments ab bit

* combine html-comment and pragma-comment and add some docs, how to use it

* Make docs simpler by removing caching info

* change h2 wording

core/modules/parsers/wikiparser/rules/commentblock.js

@@ -7,6 +7,12 @@ Wiki text block rule for HTML comments. For example:
 
 ```
 <!-- This is a comment -->
+\define macroX()
+<!-- This is a comment -->
+xxxx
+\end
+<!-- This is a comment -->
+
 ```
 
 Note that the syntax for comments is simplified to an opening "<!--" sequence and a closing "-->" sequence -- HTML itself implements a more complex format (see http://ostermiller.org/findhtmlcomment.html)
@@ -19,7 +25,7 @@ Note that the syntax for comments is simplified to an opening "<!--" sequence an
 "use strict";
 
 exports.name = "commentblock";
-exports.types = {block: true};
+exports.types = {block:true, pragma:true};
 
 exports.init = function(parser) {
 	this.parser = parser;

editions/test/tiddlers/tests/test-wikitext-parser.js

@@ -117,7 +117,14 @@ describe("WikiText parser tests", function() {
 			[ { type : 'set', attributes : { name : { type : 'string', value : 'myMacro' }, value : { type : 'string', value : 'nothing' } }, children : [  ], params : [  ], isMacroDefinition : true } ]
 
 		);
+	});
 
+	it("should parse comment in pragma area. Comment will be INVISIBLE", function() {
+		expect(parse("<!-- comment in pragma area -->\n\\define aMacro()\nnothing\n\\end\n")).toEqual(
+
+			[ { type : 'set', attributes : { name : { type : 'string', value : 'aMacro' }, value : { type : 'string', value : 'nothing' } }, children : [  ], params : [  ], isMacroDefinition : true } ]
+
+		);
 	});
 
 	it("should parse inline macro calls", function() {

editions/tw5.com/tiddlers/wikitext/HTML in WikiText.tid

@@ -1,10 +1,12 @@
 caption: HTML
 created: 20131205160816081
-modified: 20201125094415933
+modified: 20210614100305329
 tags: WikiText
 title: HTML in WikiText
 type: text/vnd.tiddlywiki
 
+! HTML tags and comments
+
 HTML tags and comments can be used directly in WikiText. For example:
 
 ```
@@ -14,7 +16,22 @@ This is my nice and simple block of text. HelloThere
 </article>
 ```
 
-[[Widgets share the same syntax as HTML tags|Widgets in WikiText]], and so the following information applies to them, too.
+!! Pragma Comments
+
+<<.from-version 5.2.0>> Comments can now be freely intermixed with pragmas as well as within the main body of a block of wikitext.
+
+```
+<!-- NEW: Comment that describes the macro -->
+\define test()
+some text <!-- inline comment -->
+\end
+
+<<test>>
+```
+
+! Important
+
+<<.tip """[[Widgets share the same syntax as HTML tags|Widgets in WikiText]], and so the following information applies to them, too.""">>
 
 ! Block mode versus Inline mode