.globalsearch uses a submit button instead of input[@type='submit']

AFFECTS:

• All pages
• xwiki:XWiki.WatchListRss
• xwiki:Main.WebHome
• etc.

ERROR:

• org.xwiki.test.webstandards.CustomDutchWebGuidelinesValidationTest.Validating HTML5 Dutch Web Guidelines validity for: xwiki:XWiki.WatchListRss executed with credentials Admin:admin (from org.xwiki.test.webstandards.AllTests)
• ERROR: At least one form does not have a <submit> button.

INVALIDATES:

• Dutch Guidelines: validateRpd13s4()
  • https://github.com/xwiki/xwiki-platform/blob/master/xwiki-platform-tools/xwiki-platform-tool-standards-validator/src/main/java/org/xwiki/validator/DutchWebGuidelinesValidator.java#L1239-L1258
• R-pd.13.4 "Avoid automatic redirection during interaction with forms."

EXPLANATION:

• The code is looking for //input[@type='submit'] or //input[@type='image']
• The current .globalsearch is using <button type="submit" class="btn" title="Search">

FIXES:

• VAR1: Replace the usage of button[@type='submit'] with an input in the template
• VAR2: Add the button@type='submit' use case in the test's function validateRpd13s4() since the usage is valid. You can read here more about the usage difference https://css-tricks.com/use-button-element/ . Short version: the button element can be more easily styled with CSS, which is our case with our Search button.