replace assert.h with cassert

The former was deprecated with C++14.

According to the C++11 and C++17 standards, both files are identical.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

src/fs/Charset.cxx

@@ -31,8 +31,7 @@
 #endif
 
 #include <algorithm>
-
-#include <assert.h>
+#include <cassert>
 
 #ifdef HAVE_FS_CHARSET
 

src/fs/Path.hxx

@@ -23,10 +23,9 @@
 #include "util/Compiler.h"
 #include "Traits.hxx"
 
+#include <cassert>
 #include <string>
 
-#include <assert.h>
-
 class AllocatedPath;
 
 /**

src/fs/Traits.hxx

@@ -29,10 +29,9 @@
 #include <tchar.h>
 #endif
 
+#include <cassert>
 #include <string>
 
-#include <assert.h>
-
 #ifdef _WIN32
 #define PATH_LITERAL(s) _T(s)
 #else

src/fs/io/FileOutputStream.hxx

@@ -38,7 +38,8 @@
 #include "system/FileDescriptor.hxx"
 #endif
 
-#include <assert.h>
+#include <cassert>
+
 #include <stdint.h>
 
 #ifdef _WIN32

src/fs/io/FileReader.cxx

@@ -32,7 +32,7 @@
 #include "system/Error.hxx"
 #include "system/Open.hxx"
 
-#include <assert.h>
+#include <cassert>
 
 #ifdef _WIN32
 

src/fs/io/PeekReader.cxx

@@ -20,8 +20,8 @@
 #include "PeekReader.hxx"
 
 #include <algorithm>
+#include <cassert>
 
-#include <assert.h>
 #include <string.h>
 
 const void *

src/fs/io/TextFile.cxx

@@ -23,7 +23,7 @@
 #include "BufferedReader.hxx"
 #include "fs/Path.hxx"
 
-#include <assert.h>
+#include <cassert>
 
 TextFile::TextFile(Path path_fs)
 	:file_reader(std::make_unique<FileReader>(path_fs)),