[ADF-4152] Updated folder structure of core docs (#4415)

* [ADF-4152] Moved core library docs into subfolders

* [ADF-4152] Moved core library docs into subfolders

* [ADF-4152] Manual fixes to core doc file links

* [ADF-4152] Further automatic + manual link tidying

docs/core/services/highlight-transform.service.md

@@ -0,0 +1,52 @@
+---
+Title: Highlight Transform service
+Added: v2.0.0
+Status: Active
+Last reviewed: 2018-11-13
+---
+
+# [Highlight Transform service](../../../lib/core/services/highlight-transform.service.ts "Defined in highlight-transform.service.ts")
+
+Adds HTML to a string to highlight chosen sections.
+
+## Class members
+
+### Methods
+
+-   **highlight**(text: `string`, search: `string`, wrapperClass: `string` = `"adf-highlight"`): [`HighlightTransformResult`](../../../lib/core/services/highlight-transform.service.ts)<br/>
+    Searches for `search` string(s) within `text` and highlights all occurrences.
+    -   _text:_ `string`  - Text to search within
+    -   _search:_ `string`  - Text pattern to search for
+    -   _wrapperClass:_ `string`  - CSS class used to provide highlighting style
+    -   **Returns** [`HighlightTransformResult`](../../../lib/core/services/highlight-transform.service.ts) - New text along with boolean value to indicate whether anything was highlighted
+
+## Details
+
+A typical use case for this service is to display the results from a search engine.
+An excerpt of a retrieved document can be shown with the matching search terms
+highlighted to indicate where they were found.
+
+The service works by adding HTML &lt;span> elements around all sections of text
+that match the `search` string. You can specify multiple search strings at once by
+separating them with spaces, so passing "Apple Banana Cherry" in `search` will
+highlight any of those words individually. The &lt;span> element includes a
+`class` attribute which defaults to "highlight" but you can pass any class name
+you like using the `wrapperClass` parameter.
+
+The resulting text with HTML highlighting is returned within a [`HighlightTransformResult`](../../../lib/core/services/highlight-transform.service.ts)
+object:
+
+```ts
+interface HighlightTransformResult {
+    text: string;
+    changed: boolean;
+}
+```
+
+The `changed` flag will be false if the search string was not found (ie, no highlighting
+took place) and true otherwise.
+
+## See also
+
+-   [Text highlight pipe](../pipes/text-highlight.pipe.md)
+-   [Highlight directive](../directives/highlight.directive.md)