Added documentation about optional config

Signed-off-by: Andre Wanlin <67169551+awanlin@users.noreply.github.com>

plugins/search-backend-module-pg/README.md

@@ -14,3 +14,31 @@ other plugins.
 
 See [Backstage documentation](https://backstage.io/docs/features/search/search-engines#postgres)
 for details on how to setup Postgres based search for your Backstage instance.
+
+## Optional Configuration
+
+The following is an example of the optional configuration that can be applied when using Postgres as the search backend. Currently this is mostly for just the highlight feature:
+
+```yaml
+search:
+  pg:
+    highlightOptions:
+      useHighlight: true # Used to enable to disable the highlight feature. The default value is true
+      maxWord: 35 # Used to set the longest headlines to output. The default value is 35.
+      minWord: 15 # Used to set the shortest headlines to output. The default value is 15.
+      shortWord: 3 # Words of this length or less will be dropped at the start and end of a headline, unless they are query terms. The default value of three (3) eliminates common English articles.
+      highlightAll: false # If true the whole document will be used as the headline, ignoring the preceding three parameters. The default is false.
+      maxFragments: 0 # Maximum number of text fragments to display. The default value of zero selects a non-fragment-based headline generation method. A value greater than zero selects fragment-based headline generation (see the linked documentation above for more details).
+      fragmentDelimiter: ' ... ' # Delimiter string used to concatenate fragments. Defaults to " ... ".
+```
+
+**Note:** the highlight search term feature uses `ts_headline` which has been known to potentially impact performance. You only need this minimal config to disable it should you have issues:
+
+```yaml
+search:
+  pg:
+    highlightOptions:
+      useHighlight: false
+```
+
+The Postgres documentation on [Highlighting Results](https://www.postgresql.org/docs/current/textsearch-controls.html#TEXTSEARCH-HEADLINE) has more details.

plugins/search-backend-module-pg/config.d.ts

@@ -48,7 +48,7 @@ export interface Config {
          */
         highlightAll?: boolean;
         /**
-         * maximum number of text fragments to display. The default value of zero selects a non-fragment-based headline generation method.
+         * Maximum number of text fragments to display. The default value of zero selects a non-fragment-based headline generation method.
          * A value greater than zero selects fragment-based headline generation (see the linked documentation above for more details).
          */
         maxFragments?: number;