Support assignment operator in Snowflake

Fixes #775

Author: nene

src/languages/snowflake/snowflake.formatter.ts

@@ -328,6 +328,8 @@ export const snowflake: DialectOptions = {
       '||',
       // Generators: https://docs.snowflake.com/en/sql-reference/functions/generator.html#generator
       '=>',
+      // Assignment https://docs.snowflake.com/en/sql-reference/snowflake-scripting/let
+      ':=',
     ],
     propertyAccessOperators: [':'],
   },

test/snowflake.test.ts

@@ -54,7 +54,7 @@ describe('SnowflakeFormatter', () => {
   supportsIdentifiers(format, [`""-qq`]);
   supportsBetween(format);
   // ':' and '::' are tested later, since they should always be dense
-  supportsOperators(format, ['%', '||', '=>'], { any: true });
+  supportsOperators(format, ['%', '||', '=>', ':='], { any: true });
   supportsJoin(format, { without: ['NATURAL INNER JOIN'] });
   supportsSetOperations(format, ['UNION', 'UNION ALL', 'MINUS', 'EXCEPT', 'INTERSECT']);
   supportsLimiting(format, { limit: true, offset: true, fetchFirst: true, fetchNext: true });