Reassign Unicode for \[Rule]

[rocky]

"Rule" is not the same thing as "RightArrow". Use a Unicode glyph that matches the Mathematica symbol better. Note that the arrowhead is not a triangle, but two lines.

Fixes #146

[mmatera]

This is what I get when I use it against mathics CLI:

In[1]:= A->B
Out[1]= A ᾆ2 B

In[2]:= A->B //InputForm
Out[2]//InputForm= A ᾆ2 B

In[3]:= A ᾆ2 B
Syntax::sntxf: "A" cannot be followed by "ᾆ2 B" (line 1 of "ᾆ2 B").

Not only the symbol is wrong, but also it is not properly processed by the parser.

[rocky]

This is what I get when I use it against mathics CLI:

In[1]:= A->B Out[1]= A ᾆ2 B

In[2]:= A->B //InputForm Out[2]//InputForm= A ᾆ2 B

In[3]:= A ᾆ2 B Syntax::sntxf: "A" cannot be followed by "ᾆ2 B" (line 1 of "ᾆ2 B").

Not only the symbol is wrong, but also it is not properly processed by the parser.

What's going on is that this is coming from a different Unicode block. So I guess we change the value to something else.

Not being properly parsed by the parser is a separate and valid problem that will be addressed.