Add accessor keyword

Author: mantoni

Diff for: syntax/javascript.vim

@@ -186,7 +186,7 @@ syntax keyword jsClassKeyword           contained class
 syntax keyword jsExtendsKeyword         contained extends skipwhite skipempty nextgroup=@jsExpression
 syntax match   jsClassNoise             contained /\./
 syntax match   jsClassFuncName          contained /\<\K\k*\ze\s*[(<]/ skipwhite skipempty nextgroup=jsFuncArgs,jsFlowClassFunctionGroup
-syntax match   jsClassMethodType        contained /\<\%([gs]et\|static\)\ze\s\+\K\k*/ skipwhite skipempty nextgroup=jsAsyncKeyword,jsClassFuncName,jsClassProperty
+syntax match   jsClassMethodType        contained /\<\%([gs]et\|static\|accessor\)\ze\s\+\K\k*/ skipwhite skipempty nextgroup=jsAsyncKeyword,jsClassFuncName,jsClassProperty
 syntax region  jsClassDefinition                  start=/\<class\>/ end=/\(\<extends\>\s\+\)\@<!{\@=/ contains=jsClassKeyword,jsExtendsKeyword,jsClassNoise,@jsExpression,jsFlowClassGroup skipwhite skipempty nextgroup=jsCommentClass,jsClassBlock,jsFlowClassGroup
 syntax match   jsClassProperty          contained /\<\K\k*\ze\s*[=;]/ skipwhite skipempty nextgroup=jsClassValue,jsFlowClassDef
 syntax region  jsClassValue             contained start=/=/ end=/\_[;}]\@=/ contains=@jsExpression