color: don't split colors across lines (which confuses less -R)

Currently, less -R doesn't support colors spanning multiple lines; only
the first line will be colorized.

Instead of allowing colors to span multiple lines, the color extension
now applies colors to each line it receives, even when ui.write() is
given multiple lines in one call.

hgext/color.py

@@ -110,10 +110,7 b' def render_effects(text, effects):'
     start = [str(_effects[e]) for e in ['none'] + effects.split()]
     start = '\033[' + ';'.join(start) + 'm'
     stop = '\033[' + str(_effects['none']) + 'm'
-    if text[-1] == '\n':
-        return ''.join([start, text[:-1], stop, '\n'])
-    else:
-        return ''.join([start, text, stop])
+    return ''.join([start, text, stop])
 
 def extstyles():
     for name, ext in extensions.extensions():
@@ -141,7 +138,8 b' def style(msg, label):'
     for l in label.split():
         effects += _styles.get(l, '')
     if effects:
-        return render_effects(msg, effects)
+        return '\n'.join([render_effects(s, effects)
+                          for s in msg.split('\n')])
     return msg
 
 def popbuffer(orig, labeled=False):

tests/test-eolfilename.out

@@ -14,7 +14,7 b' f hell'
 o  hell
 o
 % test issue2039
-? foo
-bar
-? foo
-bar.baz
+? foo
+bar
+? foo
+bar.baz