Fix typo in "handing" (missing "l") (#71383) (#71399)

Co-authored-by: Gonzalo Servat <[email protected]>

Author: Adam Locke

docs/reference/ingest.asciidoc

@@ -578,7 +578,7 @@ PUT _ingest/pipeline/my-pipeline
 
 [discrete]
 [[handling-pipeline-failures]]
-=== Handing pipeline failures
+=== Handling pipeline failures
 
 A pipeline's processors run sequentially. By default, pipeline processing stops
 when one of these processors fails or encounters an error.