triangle 1.2.1: Shorten and clarify test descriptions

The current [Test] names confused me when I was doing the exercise. It
was also difficult to see which tests failed, because of long test
descriptions combined with a small window with the test results.

This PR changes the
"Returns true if the triangle is equilateral false if any side is unequal"
style in favour of a pattern that follows
"equilateral triangle returns false if any side is unequal".

exercism/problem-specifications#1483

Note for the Crystal track:

Since the the following case group descriptions do not appear in the
test file (for example, as a `describe` or a `context`), test
descriptions may be considered to be missing some context. However, this
has always been the case, so this does not worsen the state of the
world, only keep it about as bad as it always has been.

https://github.com/exercism/problem-specifications/blob/master/exercises/triangle/canonical-data.json#L22
https://github.com/exercism/problem-specifications/blob/master/exercises/triangle/canonical-data.json#L71
https://github.com/exercism/problem-specifications/blob/master/exercises/triangle/canonical-data.json#L152

exercises/triangle/spec/triangle_spec.cr

@@ -2,75 +2,75 @@ require "spec"
 require "../src/*"
 
 describe "Triangle" do
-  it "true if all sides are equal" do
+  it "all sides are equal" do
     Triangle.new([2, 2, 2]).equilateral?.should eq(true)
   end
 
-  pending "false if any side is unequal" do
+  pending "any side is unequal" do
     Triangle.new([2, 3, 2]).equilateral?.should eq(false)
   end
 
-  pending "false if no sides are equal" do
+  pending "no sides are equal" do
     Triangle.new([5, 4, 6]).equilateral?.should eq(false)
   end
 
-  pending "All zero sides are illegal, so the triangle is not equilateral" do
+  pending "all zero sides is not a triangle" do
     Triangle.new([0, 0, 0]).equilateral?.should eq(false)
   end
 
   pending "sides may be floats" do
     Triangle.new([0.5, 0.5, 0.5]).equilateral?.should eq(true)
   end
 
-  pending "true if last two sides are equal" do
+  pending "last two sides are equal" do
     Triangle.new([3, 4, 4]).isosceles?.should eq(true)
   end
 
-  pending "true if first two sides are equal" do
+  pending "first two sides are equal" do
     Triangle.new([4, 4, 3]).isosceles?.should eq(true)
   end
 
-  pending "true if first and last sides are equal" do
+  pending "first and last sides are equal" do
     Triangle.new([4, 3, 4]).isosceles?.should eq(true)
   end
 
   pending "equilateral triangles are also isosceles" do
     Triangle.new([4, 4, 4]).isosceles?.should eq(true)
   end
 
-  pending "false if no sides are equal" do
+  pending "no sides are equal" do
     Triangle.new([2, 3, 4]).isosceles?.should eq(false)
   end
 
-  pending "Sides that violate triangle inequality are not isosceles, even if two are equal (1)" do
+  pending "first triangle inequality violation" do
     Triangle.new([1, 1, 3]).isosceles?.should eq(false)
   end
 
-  pending "Sides that violate triangle inequality are not isosceles, even if two are equal (2)" do
+  pending "second triangle inequality violation" do
     Triangle.new([1, 3, 1]).isosceles?.should eq(false)
   end
 
-  pending "Sides that violate triangle inequality are not isosceles, even if two are equal (3)" do
+  pending "third triangle inequality violation" do
     Triangle.new([3, 1, 1]).isosceles?.should eq(false)
   end
 
   pending "sides may be floats" do
     Triangle.new([0.5, 0.4, 0.5]).isosceles?.should eq(true)
   end
 
-  pending "true if no sides are equal" do
+  pending "no sides are equal" do
     Triangle.new([5, 4, 6]).scalene?.should eq(true)
   end
 
-  pending "false if all sides are equal" do
+  pending "all sides are equal" do
     Triangle.new([4, 4, 4]).scalene?.should eq(false)
   end
 
-  pending "false if two sides are equal" do
+  pending "two sides are equal" do
     Triangle.new([4, 4, 3]).scalene?.should eq(false)
   end
 
-  pending "Sides that violate triangle inequality are not scalene, even if they are all different" do
+  pending "may not violate triangle inequality" do
     Triangle.new([7, 3, 2]).scalene?.should eq(false)
   end