(#11535) Update file type with Windows-specific quirks

This commit adds the following Win-specific information to the file type's documentation:

• No symlinks
• Puppet doesn't translate line-endings (that is, content is managed in binary mode)
• Paths need drive letters
• Use / in paths, not \
• Users can be groups and vice-versa
• Other maps to Everyone
• r/w/x map to FILE_GENERIC_READ, FILE_GENERIC_WRITE, and FILE_GENERIC_EXECUTE
• User permissions should be superset of group which should be superset of other
• Mapped drives are OK for file sources