Update lowercase-tokenizer.asciidoc (#21896)

Fixed typo

docs/reference/analysis/tokenizers/lowercase-tokenizer.asciidoc

@@ -5,7 +5,7 @@
 The `lowercase` tokenizer, like the
 <<analysis-letter-tokenizer, `letter` tokenizer>> breaks text into terms
 whenever it encounters a character which is not a letter, but it also
-lowecases all terms.  It is functionally equivalent to the
+lowercases all terms.  It is functionally equivalent to the
 <<analysis-letter-tokenizer, `letter` tokenizer>> combined with the
 <<analysis-lowercase-tokenfilter, `lowercase` token filter>>, but is more
 efficient as it performs both steps in a single pass.