handle lcov end line number (#105)

According to the lcov documentation, `FN` field can contain optional
end line number.

Right now the code crashes in this case.
This commit makes sure it doesn't and it's well parsed.

Ref: https://manpages.ubuntu.com/manpages/noble/man1/geninfo.1.html

```
       Following is a list of line numbers for each function name found in the source file:

         FN:<line number of function start>,(<line number of function end>,)?<function name>

       The 'end' line number is optional, and is generated only if the compiler/toolchain version
       is  recent  enough  to  generate  the  data  (e.g., gcc 9 or newer).
```

Author: Cheekie25

fastcov.py

@@ -807,9 +807,10 @@ def parseInfo(path):
                 })
                 current_data = fastcov_json["sources"][current_sf][current_test_name]
             elif line.startswith("FN:"):
-                line_num, function_name = line[3:].strip().split(",")
+                line_nums, function_name = line[3:].strip().rsplit(",", maxsplit=1)
+                line_num_start = line_nums.split(",")[0]
                 current_data["functions"][function_name] = {}
-                current_data["functions"][function_name]["start_line"] = tryParseNumber(line_num)
+                current_data["functions"][function_name]["start_line"] = tryParseNumber(line_num_start)
             elif line.startswith("FNDA:"):
                 count, function_name = line[5:].strip().split(",")
                 current_data["functions"][function_name]["execution_count"] = tryParseNumber(count)

test/functional/expected_results/combine6.expected.info

@@ -0,0 +1,29 @@
+TN:
+SF:/mnt/workspace/test/functional/cmake_project/src/source1.cpp
+FN:3,_Z3foob
+FNDA:1,_Z3foob
+FNF:1
+FNH:1
+DA:3,1
+DA:5,1
+DA:7,1001
+DA:8,1000
+DA:10,1000
+DA:11,0
+DA:14,1
+LF:7
+LH:6
+end_of_record
+TN:
+SF:/mnt/workspace/test/functional/cmake_project/src/source2.cpp
+FN:3,_Z3barbii
+FNDA:10,_Z3barbii
+FNF:1
+FNH:1
+DA:3,10
+DA:5,10
+DA:6,10
+DA:8,0
+LF:4
+LH:3
+end_of_record

test/functional/expected_results/test1.end_line_number_fn.info

@@ -0,0 +1,29 @@
+TN:
+SF:/mnt/workspace/test/functional/cmake_project/src/source1.cpp
+FN:3,10,_Z3foob
+FNDA:1,_Z3foob
+FNF:1
+FNH:1
+DA:3,1
+DA:5,1
+DA:7,1001
+DA:8,1000
+DA:10,1000
+DA:11,0
+DA:14,1
+LF:7
+LH:6
+end_of_record
+TN:
+SF:/mnt/workspace/test/functional/cmake_project/src/source2.cpp
+FN:3,10,_Z3barbii
+FNDA:10,_Z3barbii
+FNF:1
+FNH:1
+DA:3,10
+DA:5,10
+DA:6,10
+DA:8,0
+LF:4
+LH:3
+end_of_record

test/functional/run_all.sh

@@ -129,6 +129,10 @@ cmp combine3.actual.info ${TEST_DIR}/expected_results/combine3.expected.info
 coverage run -a ${TEST_DIR}/fastcov.py -C ${TEST_DIR}/expected_results/combine4a.info ${TEST_DIR}/expected_results/combine4b.info ${TEST_DIR}/expected_results/combine4c.info --lcov -o combine4.actual.info
 cmp combine4.actual.info ${TEST_DIR}/expected_results/combine4.expected.info
 
+# Combine operation - End line number in FN
+coverage run -a ${TEST_DIR}/fastcov.py -C ${TEST_DIR}/expected_results/test1.end_line_number_fn.info --lcov -o test1.end_line_number_fn.actual.info
+cmp test1.end_line_number_fn.actual.info ${TEST_DIR}/expected_results/combine6.expected.info
+
 # Combine operation - Missing TN
 coverage run -a ${TEST_DIR}/fastcov.py -C ${TEST_DIR}/expected_results/test1.no_tn.info --lcov -o test1.no_tn.actual.info
 cmp test1.no_tn.actual.info ${TEST_DIR}/expected_results/combine5.expected.info