Fix line wrapping (#180)

* Fix line wrapping

* Don't chop from tail

* Test wrapping unicode

src/format.jl

@@ -317,12 +317,12 @@ function wraplines(text, line_width=75)
 end
 
 function wrapline(text, line_width=75)
-result = ""
+    result = ""
     while length(text) > line_width
-        result*= text[1:line_width] * "\n"
-        text = text[(line_width+1):end]
+        result*= first(text, line_width) * "\n"
+        text = chop(text, head=line_width, tail=0)
     end
-result *= text
+    result *= text
 end
 
 function latex(io::IO, tex::Markdown.LaTeX)

test/formatter_test.jl

@@ -80,3 +80,17 @@ and some text
 
 """
 @test htext.content[1].content == h_ref
+
+
+# Test wrapping
+
+cows = repeat("🐄", 100)
+testcows = """
+🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄
+🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄🐄"""
+
+wcows = Weave.wrapline(cows)
+
+@test wcows == testcows
+@test length(split(wcows, "\n")[1]) == 75
+@test length(split(wcows, "\n")[2]) == 25