Add a case-sensitive substitution error rule to Vale (opensearch-project#9139)

Signed-off-by: Fanit Kolchina <[email protected]>

Author: kolchfa-aws

.github/vale/styles/OpenSearch/SubstitutionErroCaseSensitive.yml

@@ -0,0 +1,8 @@
+extends: substitution
+message: "Use '%s' instead of '%s'. Note the correct capitalization."
+ignorecase: false
+level: error
+action:
+  name: replace
+swap:
+  'Retrieval-Augmented Generation': retrieval-augmented generation

.github/vale/tests/test-style-pos.md

@@ -76,6 +76,8 @@ This sentence tests splling.
 
 This sentence tests substitution error by using the word indices.
 
+This sentence tests substitution case-sensitive error by using the word Retrieval-Augmented Generation.
+
 This sentence tests substitution suggestion due to its nature.
 
 This Table | tests capitalization

.vale.ini

@@ -61,6 +61,7 @@ OpenSearch.SpacingSlash = YES
 OpenSearch.SpacingWords = YES
 OpenSearch.Spelling = YES
 OpenSearch.StackedHeadings = YES
+OpenSearch.SubstitutionsErrorCaseSensitive = YES
 OpenSearch.SubstitutionsError = YES
 OpenSearch.SubstitutionsSuggestion = YES
 OpenSearch.TableHeadings = YES