bug: Unary plus should parse the same way as unary minus.

[samwightt]

Did you check existing issues?

• I have read all the tree-sitter docs if it relates to using the parser
• I have searched the existing issues of tree-sitter-c

Tree-Sitter CLI Version, if relevant (output of tree-sitter --version)

No response

Describe the bug

I'm working on an ast-grep version of the Rubocop ambiguous operator lint. One of the cases it needs to alert on is something +x and something -y.

When I do something -y I get an AST like this:

But when I do something +x I get a binary in the AST instead of a unary as expected:

Ruby alerts on both of these, showing that it parses both of these as a unary:

def do_something(x); end

do_something +42
do_something -42

# Running that gives us this:
 /Users/samwightt/Code/ruby/ast-grep-rubocop/demo_ambiguous_operators.rb:3: warning: ambiguous first argument; put parentheses or a space even after `+` operator
    /Users/samwightt/Code/ruby/ast-grep-rubocop/demo_ambiguous_operators.rb:4: warning: ambiguous first argument; put parentheses or a space even after `-` operator

Steps To Reproduce/Bad Parse Tree

See examples above.

Expected Behavior/Parse Tree

The parse tree for something +x and something -y should be the same structure, minus the operator and name difference:

• something + x should give a binary
• something +x should give a unary
• something+x should give a binary

Repro

something +x
something -y

[samwightt]

I'll see if I can get up a PR for this in the next few days if the maintainers are open to it 😅