[DOCS] Fix includes and broken links (#3742)

Author: jrodewig

docs/high-level.asciidoc

@@ -160,15 +160,15 @@ NEST exposes a number of important features for indexing documents into Elastics
 
 * <<indexing-documents, Indexing Documents>>
 
-* <<ingest-pipelines, Ingest Pipelines>>
+* <<pipelines, Ingest Pipelines>>
 
-* <<ingest-node, Ingest Node>>
+* <<ingest-nodes, Ingest Node>>
 
 include::{output-dir}/indexing/indexing-documents.asciidoc[]
 
-include::{output-dir}/indexing/ingest-node.asciidoc[]
+include::{output-dir}/indexing/ingest-nodes.asciidoc[]
 
-include::{output-dir}/indexing/ingest-pipelines.asciidoc[]
+include::{output-dir}/indexing/pipelines.asciidoc[]
 
 [[analysis]]
 == Analysis