The correct definitions, as per Unicode names, should be "Rightwards arrow" (for →) and "Rightwards double arrow" (for ⇒).
The error, however, stems from the fact that the editor does not differentiate between spellings with different case.
For arrows there should be two separate definitions for that in the specialchar/lang/en.js file and the editor should take letter case (rarr vs rArr) into account. This is a general problem, however, and more definitions are affected, like Œ and œ (Latin capital ligature oe and Latin small ligature oe) etc., so I am updating the ticket title.
We also seem to be missing the definitions for capital letters, or, in other words, all symbols with entities containing a capital letter (Ugrave, OElig) are missing from the lang/en.js file.
