Fix loading of consequent special unicode whitespace characters
To add multiple consequent whitespaces, do the following:
- Switch to SVG mode
- Write   (for en-space) or   (for em-space) at the place where non-compressible characters should appear.
- Now you may switch back into rich-text mode if needed, the mnemonics will be automatically converted into corresponding Unicode characters.
NOTE: non-numeric mnemonics, like   or   are not supported
(is seems like SVG standard doesn't support that)
BUG:392710