Add alias deg for ° (JuliaPhysics#764)

Author: fhagemann

docs/src/defaultunits.md

@@ -748,6 +748,7 @@ The steradian, a unit of spherical angle. There are 4π sr in a sphere.
 
 ```
 Unitful.°
+Unitful.deg
 ```
 
 The degree, a unit of angle. There are 360° in a circle.

src/pkgdefaults.jl

@@ -105,9 +105,10 @@ const AbsoluteScaleTemperature = Quantity{T, 𝚯, <:ScalarUnits} where T
 \nDimension: [`Unitful.NoDims`](@ref)."
 @unit rad     "rad"     Radian      1                       true true
 "    Unitful.°
+    Unitful.deg
 \nThe degree, a unit of angle. There are 360° in a circle.
 \nDimension: [`Unitful.NoDims`](@ref)."
-@unit °       "°"       Degree      pi/180                  false
+((@unit °       "°"       Degree      pi/180                  false), const deg = °)
 # For numerical accuracy, specific to the degree
 import Base: sind, cosd, tand, secd, cscd, cotd
 for (_x,_y) in ((:sin,:sind), (:cos,:cosd), (:tan,:tand),

test/runtests.jl

@@ -10,7 +10,7 @@ import Unitful:
     ac,
     mg, g, kg,
     Ra, °F, °C, K,
-    rad, mrad, °,
+    rad, mrad, °, deg,
     ms, s, minute, hr, d, yr, Hz,
     J, A, N, mol, V, mJ, eV, dyn, mN,
     mW, W,
@@ -734,6 +734,7 @@ Base.:(<=)(x::Issue399, y::Issue399) = x.num <= y.num
         @test zero(Quantity{Int, 𝐋}) isa Quantity{Int}
         @test @inferred(π/2*u"rad" + 90u"°") ≈ π        # Dimless quantities
         @test @inferred(π/2*u"rad" - 90u"°") ≈ 0        # Dimless quantities
+        @test @inferred(90u"deg" - 90u"°") == 0
         @test_throws DimensionError 1+1m                # Dim mismatched
         @test_throws DimensionError 1-1m
     end
@@ -2328,6 +2329,10 @@ end
     @test (1//2)Unitful.ϵ0 === (1//2)Unitful.ε0
     @test Unitful.Å === Unitful.angstrom
     @test 1.0Unitful.Å === 1.0Unitful.angstrom
+    @test Unitful.deg === Unitful.°
+    @test 2Unitful.° === 2Unitful.deg
+    @test u"deg" === u"°"
+    @test uparse("deg") === uparse("°")
 end
 
 module DocUnits