refactor(uncrustify): disable uncrustify for misformatted code sections

Uncrustify version 0.74 has a bug that deindents and misformats the
entire fileio.c.

src/nvim/eval/funcs.c

@@ -7066,10 +7066,12 @@ static void init_srand(uint32_t *const x)
   if (dev_urandom_state != OK) {
     // Reading /dev/urandom doesn't work, fall back to time().
 #endif
+  // uncrustify:off
     *x = time(NULL);
 #ifndef MSWIN
   }
 #endif
+  // uncrustify:on
 }
 
 static inline uint32_t splitmix32(uint32_t *const x)

src/nvim/fileio.c

@@ -3,6 +3,8 @@
 
 // fileio.c: read from and write to a file
 
+// uncrustify:off
+
 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>