kyaml: refactor command documentation into .md files from go files

No new documentation added.

kyaml/yaml/merge3/merge3.go

@@ -10,55 +10,6 @@ import (
 	"sigs.k8s.io/kustomize/kyaml/yaml/walk"
 )
 
-const Help = `
-Description:
-
-  merge3 identifies changes between an original source + updated source and merges the result
-  into a destination, overriding the destination fields where they have changed between
-  original and updated.
-
-  ### Resource MergeRules
-
-  - Resources present in the original and deleted from the update are deleted.
-  - Resources missing from the original and added in the update are added.
-  - Resources present only in the dest are kept without changes.
-  - Resources present in both the update and the dest are merged *original + update + dest => dest*.
-
-  ### Field Merge Rules
-
-  Fields are recursively merged using the following rules:
-
-  - scalars
-    - if present in either dest or updated and 'null', clear the value
-    - if unchanged between original and updated, keep dest value
-    - if changed between original and updated (added, deleted, changed), take the updated value
-
-  - non-associative lists -- lists without a merge key
-    - if present in either dest or updated and 'null', clear the value
-    - if unchanged between original and updated, keep dest value
-    - if changed between original and updated (added, deleted, changed), take the updated value
-
-  - map keys and fields -- paired by the map-key / field-name
-    - if present in either dest or updated and 'null', clear the value
-    - if present only in the dest, it keeps its value
-    - if not-present in the dest, add the delta between original-updated as a field
-    - otherwise recursively merge the value between original, updated, dest
-
-  - associative list elements -- paired by the associative key
-    - if present only in the dest, it keeps its value
-    - if not-present in the dest, add the delta between original-updated as a field
-    - otherwise recursively merge the value between original, updated, dest
-
-  ### Associative Keys
-
-  Associative keys are used to identify "same" elements within 2 different lists, and merge them.
-  The following fields are recognized as associative keys:
-
-` + "[`mountPath`, `devicePath`, `ip`, `type`, `topologyKey`, `name`, `containerPort`]" + `
-
-  Any lists where all of the elements contain associative keys will be merged as associative lists.
-`
-
 func Merge(dest, original, update *yaml.RNode) (*yaml.RNode, error) {
 	// if update == nil && original != nil => declarative deletion