add basic highlights query

runtime/queries/rebase/highlights.scm

@@ -0,0 +1,9 @@
+(operation operator: ["p" "pick" "r" "reword" "e" "edit" "s" "squash" "m" "merge" "d" "drop" "b" "break" "x" "exec"] @keyword)
+(operation operator: ["l" "label" "t" "reset"] @function)
+(operation operator: ["f" "fixup"] @function.special)
+
+(option) @operator
+(label) @string.special.symbol
+(commit) @constant
+"#" @punctuation.delimiter
+(comment) @comment