Add note to check the WTP HTML Editor is being used

README.md

@@ -45,11 +45,11 @@ Features
 ### Content Assist
 
 Content assist features are only available for dialects which have supplied
-special dialect metadata files in their JARs.  thymeleaf, thymeleaf-spring,
-thymeleaf-extras-springsecurity, and thymeleaf-extras-tiles2 projects already
-have such files.  Other dialects, however, are up to the discretion of their
-developers.  If you're developing a Thymeleaf dialect and would like to take
-advantage of content assist for your own dialect, read the section on
+special dialect metadata files in their JARs.  Many of the dialects that come
+with Thymeleaf already include such files.  Other dialects, however, are up to
+the discretion of their developers.  If you're developing a Thymeleaf dialect
+and would like to take advantage of content assist for your own dialect, read
+the section on
 [adding content assist for your dialect](#adding-content-assist-for-your-dialect).
 
 Once those help files are available, and that the JAR is in the classpath of the
@@ -83,6 +83,13 @@ suggestions as you type, autocompletion of what you've entered so far if it
 matches only one result (both of these can be invoked manually using CTRL+SPACE),
 and help text when hovering the cursor over a Thymeleaf processor.
 
+> These features are only available in the Eclipse WebTools HTML editor, which
+> may not be the default for HTML files in your Eclipse installation.  To check
+> that you're using WTP's HTML editor, right-click an HTML file >> Open with,
+> and see if HTML Editor is selected:
+> 
+> ![HTML editor example](html-editor.png)
+
 
 Adding content assist for your dialect
 --------------------------------------