[BUG] Borrowed keyword does not work

[a62690705]

Bug description

def func(borrowed y: Int) -> borrowed Int:
    return y

def main():
    var x: Int = 1
    var ref = func(x)
    print(ref)

/

Compile error:

/source/prog.mojo:1:30: error: unexpected token in expression
def func(borrowed y: Int) -> borrowed Int:
                             ^
/source/prog.mojo:1:30: error: expected ':' in function definition
def func(borrowed y: Int) -> borrowed Int:
                             ^
/source/prog.mojo:1:30: error: unexpected token in expression
def func(borrowed y: Int) -> borrowed Int:
                             ^
mojo: error: failed to parse the provided Mojo

Steps to reproduce

• Include relevant code snippet or link to code that did not work as expected.
• If applicable, add screenshots to help explain the problem.
• If using the Playground, name the pre-existing notebook that failed and the steps that led to failure.
• Include anything else that might help us debug the issue.

System information

shell

• What OS did you do install Mojo on ?

### System information:      OS             :  linux     CPU            :  skylake-avx512     Arch           :  x86_64-unknown-linux-gnu     Physical Cores :  4     Logical Cores  :  8     CPU Features   :  sse4 avx avx2 avx512f
- [ ] https://docs.modular.com/mojo/playground

• Provide version information for Mojo by pasting the output of mojo -v 24.2
• Provide Modular CLI version by pasting the output of modular -v ---