Basic patch for syntax/php.vim support of "flexible" heredoc

php.vim.patch

--- a/syntax/php.vim	2018-11-30 16:50:41.000000000 +0000
+++ b/syntax/php.vim	2019-11-12 21:23:05.870740817 +0000
@@ -379,18 +379,18 @@
 syn case match
 
 " HereDoc
-syn region phpHereDoc matchgroup=Delimiter start="\(<<<\)\@<=\(\"\=\)\z(\I\i*\)\2$" end="^\z1\(;\=$\)\@=" contained contains=phpIdentifier,phpIdentifierSimply,phpIdentifierComplex,phpBackslashSequences,phpMethodsVar,@Spell keepend extend
+syn region phpHereDoc matchgroup=Delimiter start="\(<<<\)\@<=\(\"\=\)\z(\I\i*\)\2$" end="^\s*\z1\(;\=$\)\@=" contained contains=phpIdentifier,phpIdentifierSimply,phpIdentifierComplex,phpBackslashSequences,phpMethodsVar,@Spell keepend extend
 " including HTML,JavaScript,SQL even if not enabled via options
-syn region phpHereDoc matchgroup=Delimiter start="\(<<<\)\@<=\(\"\=\)\z(\(\I\i*\)\=\(html\)\c\(\i*\)\)\2$" end="^\z1\(;\=$\)\@=" contained contains=@htmlTop,phpIdentifier,phpIdentifierSimply,phpIdentifierComplex,phpBackslashSequences,phpMethodsVar,@Spell keepend extend
-syn region phpHereDoc matchgroup=Delimiter start="\(<<<\)\@<=\(\"\=\)\z(\(\I\i*\)\=\(sql\)\c\(\i*\)\)\2$" end="^\z1\(;\=$\)\@=" contained contains=@sqlTop,phpIdentifier,phpIdentifierSimply,phpIdentifierComplex,phpBackslashSequences,phpMethodsVar,@Spell keepend extend
-syn region phpHereDoc matchgroup=Delimiter start="\(<<<\)\@<=\(\"\=\)\z(\(\I\i*\)\=\(javascript\)\c\(\i*\)\)\2$" end="^\z1\(;\=$\)\@=" contained contains=@htmlJavascript,phpIdentifierSimply,phpIdentifier,phpIdentifierComplex,phpBackslashSequences,phpMethodsVar,@Spell keepend extend
+syn region phpHereDoc matchgroup=Delimiter start="\(<<<\)\@<=\(\"\=\)\z(\(\I\i*\)\=\(html\)\c\(\i*\)\)\2$" end="^\s*\z1\(;\=$\)\@=" contained contains=@htmlTop,phpIdentifier,phpIdentifierSimply,phpIdentifierComplex,phpBackslashSequences,phpMethodsVar,@Spell keepend extend
+syn region phpHereDoc matchgroup=Delimiter start="\(<<<\)\@<=\(\"\=\)\z(\(\I\i*\)\=\(sql\)\c\(\i*\)\)\2$" end="^\s*\z1\(;\=$\)\@=" contained contains=@sqlTop,phpIdentifier,phpIdentifierSimply,phpIdentifierComplex,phpBackslashSequences,phpMethodsVar,@Spell keepend extend
+syn region phpHereDoc matchgroup=Delimiter start="\(<<<\)\@<=\(\"\=\)\z(\(\I\i*\)\=\(javascript\)\c\(\i*\)\)\2$" end="^\s*\z1\(;\=$\)\@=" contained contains=@htmlJavascript,phpIdentifierSimply,phpIdentifier,phpIdentifierComplex,phpBackslashSequences,phpMethodsVar,@Spell keepend extend
 
 " NowDoc
-syn region phpNowDoc matchgroup=Delimiter start="\(<<<\)\@<='\z(\I\i*\)'$" end="^\z1\(;\=$\)\@=" contained contains=@Spell keepend extend
+syn region phpNowDoc matchgroup=Delimiter start="\(<<<\)\@<='\z(\I\i*\)'$" end="^\s*\z1\(;\=$\)\@=" contained contains=@Spell keepend extend
 " including HTML,JavaScript,SQL even if not enabled via options
-syn region phpNowDoc matchgroup=Delimiter start="\(<<<\)\@<='\z(\(\I\i*\)\=\(html\)\c\(\i*\)\)'$" end="^\z1\(;\=$\)\@=" contained contains=@htmlTop,@Spell keepend extend
-syn region phpNowDoc matchgroup=Delimiter start="\(<<<\)\@<='\z(\(\I\i*\)\=\(sql\)\c\(\i*\)\)'$" end="^\z1\(;\=$\)\@=" contained contains=@sqlTop,@Spell keepend extend
-syn region phpNowDoc matchgroup=Delimiter start="\(<<<\)\@<='\z(\(\I\i*\)\=\(javascript\)\c\(\i*\)\)'$" end="^\z1\(;\=$\)\@=" contained contains=@htmlJavascript,@Spell keepend extend
+syn region phpNowDoc matchgroup=Delimiter start="\(<<<\)\@<='\z(\(\I\i*\)\=\(html\)\c\(\i*\)\)'$" end="^\s*\z1\(;\=$\)\@=" contained contains=@htmlTop,@Spell keepend extend
+syn region phpNowDoc matchgroup=Delimiter start="\(<<<\)\@<='\z(\(\I\i*\)\=\(sql\)\c\(\i*\)\)'$" end="^\s*\z1\(;\=$\)\@=" contained contains=@sqlTop,@Spell keepend extend
+syn region phpNowDoc matchgroup=Delimiter start="\(<<<\)\@<='\z(\(\I\i*\)\=\(javascript\)\c\(\i*\)\)'$" end="^\s*\z1\(;\=$\)\@=" contained contains=@htmlJavascript,@Spell keepend extend
 syn case ignore
 
 " Parent