[DOCS] Fix typo (#67230) (#67395)

Co-authored-by: Łukasz Grajewski <grajewski.lukasz@wp.pl>

docs/painless/painless-lang-spec/painless-operators-numeric.asciidoc

@@ -268,7 +268,7 @@ decrement.
 
 [source,ANTLR4]
 ----
-pre_increment: '--' ( variable | field );
+pre_decrement: '--' ( variable | field );
 ----
 
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