Allows whitespace-only macro/procedure to be closed by \end (#7911)

* Added some passing macro definition parsing tests

* Added two failing tests to illustrate bug #3460

* Allow \end to end an whitespace only/empty macro definition. Fixes #3460

* Added some passing procedure definition tests

* Added two failing procedure tests to illustrate bug #3460

* Allow \end to end a whitespace only/empty procedure/function/widget definition. Fixes #3640

* Fixed wording of comment

editions/test/tiddlers/tests/data/procedures/IndentedEnd.tid

@@ -0,0 +1,16 @@
+title: Procedures/IndentedEnd
+description: \end line starting with whitespace ends a procedure body
+type: text/vnd.tiddlywiki-multiple
+tags: [[$:/tags/wiki-test-spec]]
+
+title: Output
+
+\procedure hello()
+ hello \end
+  \end
+
+Out: <<hello>>
++
+title: ExpectedResult
+
+<p>Out:  hello \end</p>