add experimental tree-sitter grammar

tree-sitter-mers/queries/highlights.scm

@@ -0,0 +1,14 @@
+(string) @string
+(variable) @variable
+(number) @number
+(chain_dot) @punctuation.delimeter
+
+(if_if) @keyword.control.conditional
+(if_else) @keyword.control.conditional
+
+(func_arrow) @function
+
+(block_start) @punctuation.bracket
+(block_end) @punctuation.bracket
+(tuple_start) @punctuation.bracket
+(tuple_end) @punctuation.bracket