Minor cleanup

clangd needs to respect clang-format files when inserting headers up
top.

[ci skip]

src/builtin_string.cpp

@@ -1,8 +1,6 @@
 // Implementation of the string builtin.
 #include "config.h"  // IWYU pragma: keep
 
-#include <functional>
-
 #define PCRE2_CODE_UNIT_WIDTH WCHAR_T_BITS
 #ifdef _WIN32
 #define PCRE2_STATIC
@@ -16,6 +14,7 @@
 #include <cstdlib>
 #include <cwchar>
 #include <cwctype>
+#include <functional>
 #include <iterator>
 #include <memory>
 #include <string>

src/reader.cpp

@@ -102,8 +102,6 @@
 /// The name of the function for getting the input mode indicator.
 #define MODE_PROMPT_FUNCTION_NAME L"fish_mode_prompt"
 
-/// The default title for the reader. This is used by reader_readline.
-
 /// The maximum number of characters to read from the keyboard without repainting. Note that this
 /// readahead will only occur if new characters are available for reading, fish will never block for
 /// more input without repainting.