fix(formatter_graphql): improve major prettier diffs (#23419)

Fixed some minor formatting diffs by checking real world repo.

crates/oxc_formatter_graphql/src/print/value.rs

@@ -127,8 +127,14 @@ fn write_block_string(body: &str, f: &mut GraphqlFormatter<'_, '_>) {
 
     // Prettier: re-escape, then `lines.length === 1` → trim,
     // all-blank → drop everything.
-    let mut lines: Vec<String> =
-        cooked_lines.iter().map(|l| l.cow_replace("\"\"\"", "\\\"\"\"").into_owned()).collect();
+    // Trailing spaces/tabs are trimmed per line: Prettier's doc printer trims
+    // them at every hardline. The core printer does the same, but a line
+    // followed by a blank-line run gets its break from raw `\n` text (see
+    // `write_block_string_break`), which bypasses that trim — so trim here.
+    let mut lines: Vec<String> = cooked_lines
+        .iter()
+        .map(|l| l.trim_end_matches([' ', '\t']).cow_replace("\"\"\"", "\\\"\"\"").into_owned())
+        .collect();
     if lines.len() == 1 {
         lines[0] = lines[0].trim().to_string();
     }

crates/oxc_formatter_graphql/tests/fixtures/format/block-string-trailing-whitespace.graphql

@@ -0,0 +1,24 @@
+type A {
+  """
+  Trailing spaces after this sentence.   
+
+  Trailing tab after this sentence.	
+  Last line before closing quotes also has them.  
+  """
+  a: String
+
+  """
+  The line below is whitespace-only, deeper than the common indent:
+      
+  It must become a blank line, not indented whitespace.
+  """
+  b: String
+
+  """
+  Multiple blank lines below keep their run length:
+     
+      
+  even when they are whitespace-only in the source.
+  """
+  c: String
+}

crates/oxc_formatter_graphql/tests/fixtures/format/block-string-trailing-whitespace.graphql.snap

@@ -0,0 +1,87 @@
+---
+source: crates/oxc_formatter_graphql/tests/fixtures/mod.rs
+---
+==================== Input ====================
+type A {
+  """
+  Trailing spaces after this sentence.   
+
+  Trailing tab after this sentence.	
+  Last line before closing quotes also has them.  
+  """
+  a: String
+
+  """
+  The line below is whitespace-only, deeper than the common indent:
+      
+  It must become a blank line, not indented whitespace.
+  """
+  b: String
+
+  """
+  Multiple blank lines below keep their run length:
+     
+      
+  even when they are whitespace-only in the source.
+  """
+  c: String
+}
+
+==================== Output ====================
+------------------
+{ printWidth: 80 }
+------------------
+type A {
+  """
+  Trailing spaces after this sentence.
+
+  Trailing tab after this sentence.
+  Last line before closing quotes also has them.
+  """
+  a: String
+
+  """
+  The line below is whitespace-only, deeper than the common indent:
+
+  It must become a blank line, not indented whitespace.
+  """
+  b: String
+
+  """
+  Multiple blank lines below keep their run length:
+
+
+  even when they are whitespace-only in the source.
+  """
+  c: String
+}
+
+-------------------
+{ printWidth: 100 }
+-------------------
+type A {
+  """
+  Trailing spaces after this sentence.
+
+  Trailing tab after this sentence.
+  Last line before closing quotes also has them.
+  """
+  a: String
+
+  """
+  The line below is whitespace-only, deeper than the common indent:
+
+  It must become a blank line, not indented whitespace.
+  """
+  b: String
+
+  """
+  Multiple blank lines below keep their run length:
+
+
+  even when they are whitespace-only in the source.
+  """
+  c: String
+}
+
+===================== End =====================