Fix typo in literal_pow overload

[jpfairbanks]

When you hit the error condition in literal_pow you get an error with rem2pi in it. That is a copy-paste-edit mistake from a few lines up:

function Base.rem2pi(x::Symbolic, mode::Base.RoundingMode)
    T = symtype(x)
    T <: Number ? term(rem2pi, x, mode) : error_f_symbolic(rem2pi, T)
end

was probably copied into

function Base.literal_pow(::typeof(^), x::Symbolic, ::Val{p}) where {p}
    T = symtype(x)
    T <: Number ? Base.:^(x, p) : error_f_symbolic(rem2pi, T)
end

This PR just fixes the typo.

[github-actions[bot]]

Benchmark Results

	master	7089c9820d3f05...	master/7089c9820d3f05...
overhead/acrule/a+2	0.727 ± 0.016 μs	0.743 ± 0.021 μs	0.979
overhead/acrule/a+2+b	0.707 ± 0.013 μs	0.716 ± 0.017 μs	0.987
overhead/acrule/a+b	0.258 ± 0.0081 μs	0.254 ± 0.011 μs	1.02
overhead/acrule/noop:Int	26.2 ± 0.93 ns	25 ± 0.06 ns	1.05
overhead/acrule/noop:Sym	0.0367 ± 0.0053 μs	0.0365 ± 0.0051 μs	1.01
overhead/rule/noop:Int	0.0441 ± 0.00051 μs	0.044 ± 0.0011 μs	1
overhead/rule/noop:Sym	0.054 ± 0.0026 μs	0.0546 ± 0.0032 μs	0.99
overhead/rule/noop:Term	0.0543 ± 0.0026 μs	0.0544 ± 0.0028 μs	0.997
overhead/ruleset/noop:Int	0.128 ± 0.0035 μs	0.129 ± 0.0034 μs	0.992
overhead/ruleset/noop:Sym	0.152 ± 0.0041 μs	0.159 ± 0.0043 μs	0.958
overhead/ruleset/noop:Term	3.46 ± 0.12 μs	3.21 ± 0.13 μs	1.08
overhead/simplify/noop:Int	0.14 ± 0.0028 μs	0.147 ± 0.0023 μs	0.952
overhead/simplify/noop:Sym	0.157 ± 0.0035 μs	0.164 ± 0.0038 μs	0.959
overhead/simplify/noop:Term	0.0364 ± 0.0019 ms	0.0362 ± 0.0014 ms	1
overhead/simplify/randterm (+, *):serial	0.0868 ± 0.001 s	0.0855 ± 0.0008 s	1.01
overhead/simplify/randterm (+, *):thread	0.0522 ± 0.032 s	0.0508 ± 0.03 s	1.03
overhead/simplify/randterm (/, *):serial	0.209 ± 0.0052 ms	0.212 ± 0.0059 ms	0.982
overhead/simplify/randterm (/, *):thread	0.242 ± 0.0063 ms	0.241 ± 0.0064 ms	1.01
overhead/substitute/a	0.0631 ± 0.0013 ms	0.0597 ± 0.0014 ms	1.06
overhead/substitute/a,b	0.0553 ± 0.0014 ms	0.0528 ± 0.0015 ms	1.05
overhead/substitute/a,b,c	17.1 ± 0.7 μs	17.7 ± 0.58 μs	0.969
polyform/easy_iszero	30.4 ± 1.7 μs	29 ± 2.1 μs	1.05
polyform/isone	2.79 ± 0.01 ns	2.79 ± 0.01 ns	1
polyform/iszero	1.18 ± 0.027 ms	1.09 ± 0.027 ms	1.08
polyform/simplify_fractions	1.72 ± 0.039 ms	1.56 ± 0.031 ms	1.1
time_to_load	4.49 ± 0.026 s	4.52 ± 0.016 s	0.992

Benchmark Plots

A plot of the benchmark results have been uploaded as an artifact to the workflow run for this PR. Go to "Actions"->"Benchmark a pull request"->[the most recent run]->"Artifacts" (at the bottom).