Fix python comment copy logic in python.kak

And introduce the first unit test that sources bundled support
scripts.

Fixes #860

rc/core/python.kak

@@ -60,8 +60,8 @@ def -hidden _python_indent_on_new_line %{
         # cleanup trailing whitespaces from previous line
         try %{ exec -draft k <a-x> s \h+$ <ret> d }
         # copy '#' comment prefix and following white spaces
-        try %{ exec -draft k x s ^\h*\K#\h* <ret> y j p }
-        # indent after :
+        try %{ exec -draft k x s ^\h*#\h* <ret> y jgh P }
+        # indent after line ending with :
         try %{ exec -draft <space> k x <a-k> :$ <ret> j <a-gt> }
     }
 }

share/kak/rc

@@ -0,0 +1 @@
+../../rc

test/regression/860-python-incorrect-commenting/cmd

@@ -0,0 +1 @@
+<a-j>welc<ret><esc>

test/regression/860-python-incorrect-commenting/in

@@ -0,0 +1,2 @@
+# comment
+if haha

test/regression/860-python-incorrect-commenting/out

@@ -0,0 +1,2 @@
+# comment
+# if haha

test/regression/860-python-incorrect-commenting/rc

@@ -0,0 +1,4 @@
+source "%val{runtime}/colors/default.kak"
+source "%val{runtime}/rc/core/formatter.kak"
+source "%val{runtime}/rc/core/python.kak"
+set buffer filetype python