fix: handle WITH in ALTER statement splitting (#728)

- Add `WITH_KW` to ALTER DDL splitter fallback handling
- Fix splitting for `ALTER TEXT SEARCH CONFIGURATION ... ALTER MAPPING
... WITH ...`
- Add a regression SQL test covering text search configuration ALTER
syntax

fixes #724

Author: psteinroe

crates/pgls_statement_splitter/src/splitter/ddl.rs

@@ -13,5 +13,5 @@ pub(crate) fn create(p: &mut Splitter) -> SplitterResult {
 pub(crate) fn alter(p: &mut Splitter) -> SplitterResult {
     p.expect(SyntaxKind::ALTER_KW)?;
 
-    unknown(p, &[SyntaxKind::ALTER_KW])
+    unknown(p, &[SyntaxKind::ALTER_KW, SyntaxKind::WITH_KW])
 }

crates/pgls_statement_splitter/tests/data/alter_text_search_configuration__1.sql

@@ -0,0 +1,3 @@
+ALTER TEXT SEARCH CONFIGURATION schema.config_name
+ALTER MAPPING FOR asciiword, asciihword, hword_asciipart, word, hword, hword_part
+WITH unaccent, schema.dictionary_name;