unicode -> Unicode

Per https://translatewiki.net/wiki/Thread:Support/About_MathJax:Mathmenu-genericfonts/en
Remove double space

Reported at https://translatewiki.net/wiki/Thread:Support/About_MathJax:Mathmenu-BadURL/en
Capitalize OTF and WOFF

Reported at https://translatewiki.net/wiki/Thread:Support/About_MathJax:Mathmenu-wofforotffonts/nl
Replace e.g. by for example and add puctuation

Reported at https://translatewiki.net/wiki/Thread:Support/About_MathJax:Mathmenu-PercentScale/en
Capitalize SVG

Reported at https://translatewiki.net/wiki/Thread:Support/About_MathJax:Mathmenu-svgfonts/en
Write commands in lower case

Per https://translatewiki.net/wiki/Thread:Support/About_MathJax:Mathmenu-TeXCommands/en
Consistency updates for UI string fomatting

* Punctuation for error strings
* Remove double spaces
* Remove inconsistent use of capital letters (somewhat Title Casey)

Reported in:
* https://translatewiki.net/wiki/Thread:Support/About_MathJax:Htmlcss-CantLoadWebFont/en
* https://translatewiki.net/wiki/Thread:Support/About_MathJax:Mathmenu-eotffonts/en