Correctly tokenize nested comments in Databricks, Clickhouse, and ANSI (apache#2044)

Author: jmhain

src/dialect/ansi.rs

@@ -34,7 +34,7 @@ impl Dialect for AnsiDialect {
         true
     }
 
-    // The SQL standard explictly states that block comments nest.
+    /// The SQL standard explicitly states that block comments nest.
     fn supports_nested_comments(&self) -> bool {
         true
     }

src/dialect/clickhouse.rs

@@ -95,8 +95,8 @@ impl Dialect for ClickHouseDialect {
         true
     }
 
-    // Supported since 2020.
-    // See <https://clickhouse.com/docs/whats-new/changelog/2020#backward-incompatible-change-2>
+    /// Supported since 2020.
+    /// See <https://clickhouse.com/docs/whats-new/changelog/2020#backward-incompatible-change-2>
     fn supports_nested_comments(&self) -> bool {
         true
     }

src/dialect/databricks.rs

@@ -80,7 +80,7 @@ impl Dialect for DatabricksDialect {
         true
     }
 
-    // https://docs.databricks.com/aws/en/sql/language-manual/sql-ref-syntax-comment
+    /// See <https://docs.databricks.com/aws/en/sql/language-manual/sql-ref-syntax-comment>
     fn supports_nested_comments(&self) -> bool {
         true
     }
@@ -89,4 +89,5 @@ impl Dialect for DatabricksDialect {
     fn supports_string_literal_backslash_escape(&self) -> bool {
         true
     }
+
 }