Automated Resyntax fixes

This is an automated change generated by Resyntax.

#### Pass 1

Applied 1 fix to [`drracket/drracket/private/syncheck/blueboxes-gui.rkt`](../blob/HEAD/drracket/drracket/private/syncheck/blueboxes-gui.rkt)

  * Line 2, `tidy-require`: Keep imports in `require` sorted and grouped by phase, with collections before files.

Applied 12 fixes to [`drracket/drracket/private/syncheck/gui.rkt`](../blob/HEAD/drracket/drracket/private/syncheck/gui.rkt)

  * Line 21, `tidy-require`: Keep imports in `require` sorted and grouped by phase, with collections before files.
  * Line 385, `let-to-define`: Internal definitions are recommended instead of `let` expressions, to reduce nesting.
  * Line 403, `define-lambda-to-define`: The `define` form supports a shorthand for defining functions (including function-returning functions).
  * Line 2141, `let-to-define`: Internal definitions are recommended instead of `let` expressions, to reduce nesting.
  * Line 2192, `let-to-define`: Internal definitions are recommended instead of `let` expressions, to reduce nesting.
  * Line 2356, `inline-unnecessary-define`: This variable is returned immediately and can be inlined.
  * Line 2464, `define-lambda-to-define`: The `define` form supports a shorthand for defining functions (including function-returning functions).
  * Line 2612, `let-to-define`: Internal definitions are recommended instead of `let` expressions, to reduce nesting.
  * Line 2640, `let-to-define`: Internal definitions are recommended instead of `let` expressions, to reduce nesting.
  * Line 2650, `let-to-define`: Internal definitions are recommended instead of `let` expressions, to reduce nesting.
  * Line 2726, `cond-let-to-cond-define`: Internal definitions are recommended instead of `let` expressions, to reduce nesting.
  * Line 2755, `flat-contract-migration`: flat-contract is a legacy form for constructing contracts from predicates; predicates can be used directly as contracts now.

Applied 1 fix to [`drracket/drracket/private/syncheck/intf.rkt`](../blob/HEAD/drracket/drracket/private/syncheck/intf.rkt)

  * Line 3, `tidy-require`: Keep imports in `require` sorted and grouped by phase, with collections before files.

#### Pass 2

Applied 6 fixes to [`drracket/drracket/private/syncheck/gui.rkt`](../blob/HEAD/drracket/drracket/private/syncheck/gui.rkt)

  * Line 21, `tidy-require`: Keep imports in `require` sorted and grouped by phase, with collections before files.
  * Line 387, `let-to-define`: Internal definitions are recommended instead of `let` expressions, to reduce nesting.
  * Line 403, `let-to-define`: Internal definitions are recommended instead of `let` expressions, to reduce nesting.
  * Line 2090, `let-to-define`: Internal definitions are recommended instead of `let` expressions, to reduce nesting.
  * Line 2588, `let-to-define`: Internal definitions are recommended instead of `let` expressions, to reduce nesting.
  * Line 2598, `let-to-define`: Internal definitions are recommended instead of `let` expressions, to reduce nesting.

## Summary

Fixed 20 issues in 3 files.

  * Fixed 11 occurrences of `let-to-define`
  * Fixed 4 occurrences of `tidy-require`
  * Fixed 2 occurrences of `define-lambda-to-define`
  * Fixed 1 occurrence of `inline-unnecessary-define`
  * Fixed 1 occurrence of `cond-let-to-cond-define`
  * Fixed 1 occurrence of `flat-contract-migration`

drracket/drracket/private/syncheck/blueboxes-gui.rkt

@@ -1,23 +1,23 @@
 #lang racket/base
-(require framework
+(require browser/external
+         data/interval-map
+         drracket/private/rectangle-intersect
+         framework
          framework/private/coroutine
-         racket/gui/base
+         framework/private/logging-timer
+         images/icons/misc
+         net/url
          racket/class
-         racket/math
+         racket/gui/base
          racket/match
+         racket/math
          racket/runtime-path
          racket/set
-         data/interval-map
-         images/icons/misc
-         drracket/private/rectangle-intersect
-         string-constants
-         framework/private/logging-timer
          scribble/blueboxes
-         net/url
-         browser/external
-         setup/xref
          scribble/xref
-         setup/collects)
+         setup/collects
+         setup/xref
+         string-constants)
 (provide docs-text-defs-mixin
          docs-text-ints-mixin
          docs-editor-canvas-mixin