textsearch: fix kernel-doc warnings and add kernel-api section

Make lib/textsearch.c usable as kernel-doc.
Add textsearch() function family to kernel-api documentation.
Fix kernel-doc warnings in <linux/textsearch.h>:
  ../include/linux/textsearch.h:65: warning: Incorrect use of kernel-doc format:
	* get_next_block - fetch next block of data
  ../include/linux/textsearch.h:82: warning: Incorrect use of kernel-doc format:
	* finish - finalize/clean a series of get_next_block() calls

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/textsearch.h b/include/linux/textsearch.h
index 0494db3..13770cf 100644
--- a/include/linux/textsearch.h
+++ b/include/linux/textsearch.h
@@ -62,7 +62,7 @@ struct ts_config
 	int 			flags;
 
 	/**
-	 * get_next_block - fetch next block of data
+	 * @get_next_block: fetch next block of data
 	 * @consumed: number of bytes consumed by the caller
 	 * @dst: destination buffer
 	 * @conf: search configuration
@@ -79,7 +79,7 @@ struct ts_config
 						  struct ts_state *state);
 
 	/**
-	 * finish - finalize/clean a series of get_next_block() calls
+	 * @finish: finalize/clean a series of get_next_block() calls
 	 * @conf: search configuration
 	 * @state: search state
 	 *