perf: limit look back for preceding @ to 1 char

Author: biinari

syntax/blade.vim

@@ -25,7 +25,7 @@ else
     setlocal iskeyword+=@-@
 endif
 
-syn region  bladeEcho       matchgroup=bladeDelimiter start="@\@<!{{" end="}}"  contains=@bladePhp,bladePhpParenBlock  containedin=ALLBUT,@bladeExempt keepend
+syn region  bladeEcho       matchgroup=bladeDelimiter start="@\@1<!{{" end="}}"  contains=@bladePhp,bladePhpParenBlock  containedin=ALLBUT,@bladeExempt keepend
 syn region  bladeEcho       matchgroup=bladeDelimiter start="{!!" end="!!}"  contains=@bladePhp,bladePhpParenBlock  containedin=ALLBUT,@bladeExempt keepend
 syn region  bladeComment    matchgroup=bladeDelimiter start="{{--" end="--}}"  contains=bladeTodo  containedin=ALLBUT,@bladeExempt keepend