kv-parser small fix (#153)

Fixed small error of the phrase "parser" being duplicated in text and in
a codeblock.

Author: zsoltgyulai94

doc/_admin-guide/120_Parser/002_Parsing_key-value_pairs/000_kv_parser_options.md

@@ -1,6 +1,6 @@
 ---
 title: Options of key=value parsers
-parser: kv-parser
+parser: kv
 prefix: kv
 id: adm-parser-kv-opt
 description: >-