oddities with shorttag off

Found this by accident, after disabling shorttags parsing after working a rather large file that caused syntax parsing to take a few seconds...

shorttags not disabled (that is, the default)

(note that these are not short tags, but echo tags)

with `php_noShortTags=1`

with `php_noShortTags=1`, if I remove the `` be on a line with code (doesn't have to be a single line with the opening `` closing on its own line. Only after i save and quit and reopen the file (or save and `:e!`). Likewise if i open a file with the bug, removing the trigger won't fix it, until I reload the file. Whatever is causing it is "sticky".

The issue is in the Vim syntax file for PHP, likely in syntax/php.vim. Start by examining how shorttags are toggled with php_noShortTags and how regions for and echo tags are defined. Reproduce the bug with the provided examples to see the sticky highlighting behavior. Look for syntax region definitions that might incorrectly nest or fail to reset when the closing tag is on its own line.

Written by the indexing model from the issue text.