Fix typos, add codespell configuration (#2262)

Fix typos

src/cycleclock.h

diff --git a/src/cycleclock.h b/src/cycleclock.h
index 23d67d7..f383b3d 100644
--- a/src/cycleclock.h
+++ b/src/cycleclock.h
@@ -230,7 +230,7 @@
   // Alpha has a cycle counter, the PCC register, but it is an unsigned 32-bit
   // integer and thus wraps every ~4s, making using it for tick counts
   // unreliable beyond this time range.  The real-time clock is low-precision,
-  // roughtly ~1ms, but it is the only option that can reasonable count
+  // roughly ~1ms, but it is the only option that can reasonable count
   // indefinitely.
   struct timeval tv;
   gettimeofday(&tv, nullptr);
@@ -238,7 +238,7 @@
 #elif defined(__hppa__) || defined(__linux__) || defined(BENCHMARK_OS_WASI)
   // Fallback for all other architectures with a recent Linux kernel, e.g.:
   // HP PA-RISC provides a user-readable clock counter (cr16), but
-  // it's not syncronized across CPUs and only 32-bit wide when programs
+  // it's not synchronized across CPUs and only 32-bit wide when programs
   // are built as 32-bit binaries.
   // Same for SH-4 and possibly others.
   // Use clock_gettime(CLOCK_MONOTONIC, ...) instead of gettimeofday

test/output_test_helper.cc

diff --git a/test/output_test_helper.cc b/test/output_test_helper.cc
index 43a1bfd..5dc42fb 100644
--- a/test/output_test_helper.cc
+++ b/test/output_test_helper.cc
@@ -30,7 +30,7 @@
 using SubMap = std::vector<std::pair<std::string, std::string>>;
 
 TestCaseList& GetTestCaseList(TestCaseID ID) {
-  // Uses function-local statics to ensure initialization occurs
+  // Uses function-local static to ensure initialization occurs
   // before first use.
   static TestCaseList lists[TC_NumID];
   return lists[ID];

tools/gbench/util.py

diff --git a/tools/gbench/util.py b/tools/gbench/util.py
index 2e91006..7847e65 100644
--- a/tools/gbench/util.py
+++ b/tools/gbench/util.py
@@ -143,7 +143,7 @@
             json_schema_version = results["context"]["json_schema_version"]
             if json_schema_version != 1:
                 print(
-                    f"In {fname}, got unnsupported JSON schema version:"
+                    f"In {fname}, got unsupported JSON schema version:"
                     f" {json_schema_version}, expected 1"
                 )
                 sys.exit(1)