Fix closing brace indentation with --trimwhitespace nonblank-lines (#2477)

Co-authored-by: calda <1811727+calda@users.noreply.github.com>

Sources/FormattingHelpers.swift

@@ -3301,6 +3301,16 @@ extension Formatter {
             guard let lastNewlineIndex = lastIndex(of: .linebreak, in: Range(range.range)) else { break }
 
             removeToken(at: lastNewlineIndex)
+
+            // If the removed linebreak was at the end of a blank line that had trailing
+            // whitespace (i.e. the preceding token is a space and the one before that is
+            // a linebreak), also remove the trailing whitespace so it doesn't end up
+            // incorrectly concatenated with the indent of the following token.
+            if token(at: lastNewlineIndex - 1)?.isSpace == true,
+               token(at: lastNewlineIndex - 2)?.isLinebreak == true
+            {
+                removeToken(at: lastNewlineIndex - 1)
+            }
         }
     }
 

Tests/Rules/BlankLinesAtEndOfScopeTests.swift

@@ -208,4 +208,28 @@ final class BlankLinesAtEndOfScopeTests: XCTestCase {
         """
         testFormatting(for: input, output, rule: .blankLinesAtEndOfScope, options: .init(typeBlankLines: .insert), exclude: [.blankLinesAtStartOfScope])
     }
+
+    func testBlankLinesAtEndOfScopeRemovedWithTrailingWhitespace() {
+        // Blank line before closing brace that has trailing whitespace should be
+        // removed correctly without leaving the whitespace on the closing brace's line
+        let input = """
+        func foo() {
+            if let bar = bar {
+                bar()
+            }
+            \("")
+        }
+        """
+
+        let output = """
+        func foo() {
+            if let bar = bar {
+                bar()
+            }
+        }
+        """
+
+        let options = FormatOptions(truncateBlankLines: false)
+        testFormatting(for: input, output, rule: .blankLinesAtEndOfScope, options: options)
+    }
 }