Assorted English grammar changes

No functional change

Resolves #567

src/thread.cpp

@@ -30,7 +30,7 @@ using namespace Search;
 
 ThreadPool Threads; // Global object
 
-/// Thread constructor launch the thread and then wait until it goes to sleep
+/// Thread constructor launches the thread and then waits until it goes to sleep
 /// in idle_loop().
 
 Thread::Thread() {
@@ -48,7 +48,7 @@ Thread::Thread() {
 }
 
 
-/// Thread destructor wait for thread termination before returning
+/// Thread destructor waits for thread termination before returning
 
 Thread::~Thread() {
 
@@ -60,7 +60,8 @@ Thread::~Thread() {
 }
 
 
-/// Thread::wait_for_search_finished() wait on sleep condition until not searching
+/// Thread::wait_for_search_finished() waits on sleep condition
+/// until not searching
 
 void Thread::wait_for_search_finished() {
 
@@ -69,7 +70,7 @@ void Thread::wait_for_search_finished() {
 }
 
 
-/// Thread::wait() wait on sleep condition until condition is true
+/// Thread::wait() waits on sleep condition until condition is true
 
 void Thread::wait(std::atomic_bool& condition) {
 
@@ -78,7 +79,7 @@ void Thread::wait(std::atomic_bool& condition) {
 }
 
 
-/// Thread::start_searching() wake up the thread that will start the search
+/// Thread::start_searching() wakes up the thread that will start the search
 
 void Thread::start_searching(bool resume) {
 
@@ -115,7 +116,7 @@ void Thread::idle_loop() {
 }
 
 
-/// ThreadPool::init() create and launch requested threads, that will go
+/// ThreadPool::init() creates and launches requested threads that will go
 /// immediately to sleep. We cannot use a constructor because Threads is a
 /// static object and we need a fully initialized engine at this point due to
 /// allocation of Endgames in the Thread constructor.
@@ -127,9 +128,9 @@ void ThreadPool::init() {
 }
 
 
-/// ThreadPool::exit() terminate threads before the program exits. Cannot be
+/// ThreadPool::exit() terminates threads before the program exits. Cannot be
 /// done in destructor because threads must be terminated before deleting any
-/// static objects, so while still in main().
+/// static objects while still in main().
 
 void ThreadPool::exit() {
 
@@ -156,7 +157,7 @@ void ThreadPool::read_uci_options() {
 }
 
 
-/// ThreadPool::nodes_searched() return the number of nodes searched
+/// ThreadPool::nodes_searched() returns the number of nodes searched
 
 int64_t ThreadPool::nodes_searched() {
 
@@ -167,8 +168,8 @@ int64_t ThreadPool::nodes_searched() {
 }
 
 
-/// ThreadPool::start_thinking() wake up the main thread sleeping in idle_loop()
-/// and start a new search, then return immediately.
+/// ThreadPool::start_thinking() wakes up the main thread sleeping in idle_loop()
+/// and starts a new search, then returns immediately.
 
 void ThreadPool::start_thinking(const Position& pos, const LimitsType& limits,
                                 StateStackPtr& states) {