Updated comments to lcov_parser.py

Updated some of the comments in lcov_parser.py -
there was a grammar mistake and a forgotten
"raises error" section in header comments.

Signed-off-by: Darya Verzhbinsky <daryaver@google.com>
Change-Id: Iffb5fc072d7371a5279138adfda4ddb910af5aef
diff --git a/lcov_parser/lcov_parser.py b/lcov_parser/lcov_parser.py
index c623efc..c5f73eb 100644
--- a/lcov_parser/lcov_parser.py
+++ b/lcov_parser/lcov_parser.py
@@ -25,7 +25,7 @@
 
 
 class LcovSyntaxError(Exception):
-  """LcovSyntaxError is raised when there is formatting issues in the ".info" file."""
+  """LcovSyntaxError is raised when there are formatting issues in the ".info" file."""
   pass
 
 
@@ -41,6 +41,10 @@
 
   Returns:
     a tuple containing the part before and the part after a ":" in the line.
+
+  Raises:
+    LcovSyntaxError: if the format of the input line doesn't match the expected
+      format.
   """
   try:
     field, value = line.split(':', 1)
@@ -67,8 +71,8 @@
     the text Record in the file.
 
   Raises:
-    LcovSyntaxError: if the format of the input file doesn't match correct
-      LCOV format.
+    LcovSyntaxError: if the format of the input file doesn't match the expected
+      format.
   """
   rec = Record()