Properly handle comment after the longest line

Author: nene

src/formatter/formatCommaPositions.ts

@@ -102,5 +102,5 @@ function trimTrailingCommas(lines: string[]): string[] {
 }
 
 function trimTrailingComments(lines: string[]): string[] {
-  return lines.map(line => line.replace(/--.*/, ''));
+  return lines.map(line => line.replace(/\s*--.*/, ''));
 }

test/options/commaPosition.ts

@@ -128,7 +128,8 @@ export default function supportsCommaPosition(format: FormatFn) {
       const result = format(
         `SELECT alpha, --comment1
         beta,--comment2
-        delta, epsilon, iota --comment3`,
+        delta, epsilon,--comm
+        iota --comment3`,
         { commaPosition: 'tabular' }
       );
       expect(result).toBe(
@@ -137,7 +138,7 @@ export default function supportsCommaPosition(format: FormatFn) {
             alpha  , --comment1
             beta   , --comment2
             delta  ,
-            epsilon,
+            epsilon, --comm
             iota --comment3
         `
       );