Bugfix: avoid splitlines in blame (#1015)

* fix: split blame output by "\n" explicitly

This avoid additional "line break" symbols in source code from being
considered as line breaks in our parser. Git seems to only ever
consider '\n' as a newline character, but python's "splitlines()" method
considers many others by default.

Refs:
https://github.com/python/cpython/blob/3.4/Objects/unicodetype_db.h#L4317-L4338
https://github.com/git/git/blob/master/blame.c#L1633-L1637

* fix: skip empty last line while parsing blame

core/commands/blame.py

@@ -214,7 +214,7 @@ def get_content(self, ignore_whitespace=False, detect_options=None, commit_hash=
             commit_hash, "--", filename_at_commit
         )
         blame_porcelain = unicodedata.normalize('NFC', blame_porcelain)
-        blamed_lines, commits = self.parse_blame(blame_porcelain.splitlines())
+        blamed_lines, commits = self.parse_blame(blame_porcelain.split('\n'))
 
         commit_infos = {
             commit_hash: self.short_commit_info(commit)
@@ -250,6 +250,9 @@ def get_content(self, ignore_whitespace=False, detect_options=None, commit_hash=
         return spacer.join(partitions_with_commits_iter)
 
     def parse_blame(self, blame_porcelain):
+        if blame_porcelain[-1] == '':
+            blame_porcelain = blame_porcelain[:-1]
+
         lines_iter = iter(blame_porcelain)
 
         blamed_lines = []