Set doc_start_line and doc_end_line to -1 for functions without docstrings

Author: sumansaurabh

integeration_test/samples/sample1.json

@@ -30,8 +30,8 @@
             "docstring": "",
             "fun_start_line": 274,
             "fun_end_line": 285,
-            "doc_start_line": 274,
-            "doc_end_line": 274,
+            "doc_start_line": -1,
+            "doc_end_line": -1,
             "annotations": [],
             "code_line_start": 274,
             "code_line_end": 285
@@ -48,8 +48,8 @@
             "docstring": "",
             "fun_start_line": 287,
             "fun_end_line": 312,
-            "doc_start_line": 287,
-            "doc_end_line": 287,
+            "doc_start_line": -1,
+            "doc_end_line": -1,
             "annotations": [],
             "code_line_start": 287,
             "code_line_end": 312
@@ -83,8 +83,8 @@
             "docstring": "",
             "fun_start_line": 354,
             "fun_end_line": 378,
-            "doc_start_line": 354,
-            "doc_end_line": 354,
+            "doc_start_line": -1,
+            "doc_end_line": -1,
             "annotations": [],
             "code_line_start": 354,
             "code_line_end": 378
@@ -118,8 +118,8 @@
                     "docstring": "",
                     "fun_start_line": 41,
                     "fun_end_line": 60,
-                    "doc_start_line": 41,
-                    "doc_end_line": 41,
+                    "doc_start_line": -1,
+                    "doc_end_line": -1,
                     "annotations": [],
                     "code_line_start": 41,
                     "code_line_end": 60
@@ -155,8 +155,8 @@
                     "docstring": "",
                     "fun_start_line": 91,
                     "fun_end_line": 122,
-                    "doc_start_line": 91,
-                    "doc_end_line": 91,
+                    "doc_start_line": -1,
+                    "doc_end_line": -1,
                     "annotations": [],
                     "code_line_start": 91,
                     "code_line_end": 122
@@ -194,8 +194,8 @@
                     "docstring": "",
                     "fun_start_line": 154,
                     "fun_end_line": 182,
-                    "doc_start_line": 154,
-                    "doc_end_line": 154,
+                    "doc_start_line": -1,
+                    "doc_end_line": -1,
                     "annotations": [],
                     "code_line_start": 154,
                     "code_line_end": 182
@@ -211,8 +211,8 @@
                     "docstring": "",
                     "fun_start_line": 184,
                     "fun_end_line": 205,
-                    "doc_start_line": 184,
-                    "doc_end_line": 184,
+                    "doc_start_line": -1,
+                    "doc_end_line": -1,
                     "annotations": [],
                     "code_line_start": 184,
                     "code_line_end": 205
@@ -225,8 +225,8 @@
                     "docstring": "",
                     "fun_start_line": 207,
                     "fun_end_line": 232,
-                    "doc_start_line": 207,
-                    "doc_end_line": 207,
+                    "doc_start_line": -1,
+                    "doc_end_line": -1,
                     "annotations": [],
                     "code_line_start": 207,
                     "code_line_end": 232