Exclude spimpl.h in docs

Author: adazem009

Doxyfile

@@ -955,7 +955,8 @@ RECURSIVE              = YES
 # Note that relative paths are relative to the directory from which doxygen is
 # run.
 
-EXCLUDE                = docs/theme
+EXCLUDE                = docs/theme \
+                         include/scratchcpp/spimpl.h
 
 # The EXCLUDE_SYMLINKS tag can be used to select whether or not files or
 # directories that are symbolic links (a Unix file system feature) are excluded