Rename the template_for header.

C++26 (I hope) is supposed to have this syntax:

```
template for( const auto &element: aggregate )
{
	...;
}
```

Thus, I've adjusted this gadget to have a similar name, to enable
simple mechanical code changes.  From Alepha, you'd use it
thus:

```
template_for( aggregate ) <=[&]( const auto &element )
{
	...;
};
```

CMakeLists.txt

@@ -38,7 +38,7 @@ add_subdirectory( comparisons.test )
 add_subdirectory( Exception.test )
 add_subdirectory( word_wrap.test )
 add_subdirectory( string_algorithms.test )
-add_subdirectory( template_for_each.test )
+add_subdirectory( template_for.test )
 add_subdirectory( tuplize_args.test )
 add_subdirectory( Thread.test )
 add_subdirectory( assertion.test )

IOStreams/IStreamable.h

@@ -7,7 +7,7 @@ static_assert( __cplusplus > 2020'99 );
 #include <istream>
 
 #include <Alepha/Capabilities.h>
-#include <Alepha/template_for_each.h>
+#include <Alepha/template_for.h>
 #include <Alepha/string_algorithms.h>
 #include <Alepha/Concepts.h>
 

IOStreams/OStreamable.h

@@ -7,7 +7,7 @@ static_assert( __cplusplus > 2020'99 );
 #include <ostream>
 
 #include <Alepha/Capabilities.h>
-#include <Alepha/template_for_each.h>
+#include <Alepha/template_for.h>
 #include <Alepha/string_algorithms.h>
 #include <Alepha/delimited_list.h>
 #include <Alepha/Concepts.h>

Testing/TableTest.h

@@ -16,7 +16,7 @@ static_assert( __cplusplus > 2020'99 );
 #include <iomanip>
 
 #include <Alepha/function_traits.h>
-#include <Alepha/template_for_each.h>
+#include <Alepha/template_for.h>
 
 #include <Alepha/IOStreams/String.h>
 

template_for.test/0.cc

@@ -1,6 +1,6 @@
 static_assert( __cplusplus > 2023'00 );
 
-#include "../template_for_each.h"
+#include "../template_for.h"
 
 #include <Alepha/Testing/test.h>
 #include <Alepha/Testing/TableTest.h>