Rename non-type template parameter/argument to "constant"

As previously discussed by CWG.
The aim is to editorially adopt some of the wording
changes made in P2841R5 to ease its review in core.

Note that not all-instance of non-type have been
mechanically replaced as [dcl] and [diff] use
the term to refer to anything that is not a type
in the context of lookup

Author: cor3ntin

source/compatibility.tex

@@ -1646,12 +1646,12 @@
 
 \diffref{temp.deduct.type}
 \change
-Allowance to deduce from the type of a non-type template argument.
+Allowance to deduce from the type of a constant template argument.
 \rationale
 In combination with the ability to declare
-non-type template arguments with placeholder types,
+constant template arguments with placeholder types,
 allows partial specializations to decompose
-from the type deduced for the non-type template argument.
+from the type deduced for the constant template argument.
 \effect
 Valid \CppXIV{} code may fail to compile
 or produce different results in this revision of \Cpp{}.

source/declarations.tex

@@ -1671,7 +1671,7 @@
 the specification of the structured binding declaration;
 
 \item otherwise, if $E$ is an unparenthesized \grammarterm{id-expression}
-naming a non-type template parameter\iref{temp.param},
+naming a constant template parameter\iref{temp.param},
 \tcode{decltype($E$)} is the type of the template parameter
 after performing any necessary
 type deduction\iref{dcl.spec.auto,dcl.type.class.deduct};
@@ -2106,9 +2106,9 @@
 and $E$ is the \grammarterm{assignment-expression}.
 \end{itemize}
 \item
-For a non-type template parameter declared with a type
+For a constant template parameter declared with a type
 that contains a placeholder type,
-\tcode{T} is the declared type of the non-type template parameter
+\tcode{T} is the declared type of the constant template parameter
 and $E$ is the corresponding template argument.
 \end{itemize}
 
@@ -7185,7 +7185,7 @@
 in the scope of \tcode{E}\iref{class.member.lookup}
 finds at least one declaration
 that is a function template whose first template parameter
-is a non-type parameter,
+is a constant parameter,
 the initializer is
 \tcode{\exposidnc{e}.get<i>()}. Otherwise, the initializer is \tcode{get<i>(\exposid{e})},
 where \tcode{get} undergoes argument-dependent lookup\iref{basic.lookup.argdep}.

source/expressions.tex

@@ -8186,7 +8186,7 @@
 expressions\iref{expr.new}, as case expressions\iref{stmt.switch},
 as enumerator initializers if the underlying type is
 fixed\iref{dcl.enum}, as array bounds\iref{dcl.array}, and
-as non-type template
+as constant template
 arguments\iref{temp.arg}.
 \end{note}
 \indextext{contextually converted constant expression of type \tcode{bool}|see{conversion, contextual}}%

source/lex.tex

@@ -2218,7 +2218,7 @@
 and let \placeholder{len} be the number of code units in \placeholder{str}
 (i.e., its length excluding the terminating null character).
 If \placeholder{S} contains a literal operator template with
-a non-type template parameter for which \placeholder{str} is
+a constant template parameter for which \placeholder{str} is
 a well-formed \grammarterm{template-argument},
 the literal \placeholder{L} is treated as a call of the form
 \begin{codeblock}

source/meta.tex

@@ -59,7 +59,7 @@
 \pnum
 The alias template
 \tcode{make_integer_sequence} denotes a specialization of
-\tcode{integer_sequence} with \tcode{N} non-type template arguments.
+\tcode{integer_sequence} with \tcode{N} constant template arguments.
 The type \tcode{make_integer_sequence<T, N>} is an alias for the type
 \tcode{integer_sequence<T, 0, 1, ..., N-1>}.
 \begin{note}

source/numerics.tex

@@ -2564,7 +2564,7 @@
 \pnum
 Each template specified in \ref{rand.eng}
 requires one or more relationships,
-involving the value(s) of its non-type template parameter(s), to hold.
+involving the value(s) of its constant template parameter(s), to hold.
 A program instantiating any of these templates
 is ill-formed
 if any such required relationship fails to hold.
@@ -3356,7 +3356,7 @@
 \pnum
 Each template specified in \ref{rand.adapt}
 requires one or more relationships,
-involving the value(s) of its non-type template parameter(s), to hold.
+involving the value(s) of its constant template parameter(s), to hold.
 A program instantiating any of these templates
 is ill-formed
 if any such required relationship fails to hold.

source/overloading.tex

@@ -3103,7 +3103,7 @@
 \item
 an explicit type conversion\iref{expr.type.conv,expr.static.cast,expr.cast}, or
 \item
-a non-type template parameter\iref{temp.arg.nontype}.
+a constant template parameter\iref{temp.arg.nontype}.
 \end{itemize}
 If the target type contains a placeholder type,
 placeholder type deduction is performed\iref{dcl.type.auto.deduct}, and
@@ -4094,13 +4094,13 @@
 A \defnx{numeric literal operator template}{literal!operator!template numeric}
 is a literal operator template whose \grammarterm{template-parameter-list}
 has a single \grammarterm{template-parameter}
-that is a non-type template parameter pack\iref{temp.variadic}
+that is a constant template parameter pack\iref{temp.variadic}
 with element type \tcode{char}.
 A \defnx{string literal operator template}{literal!operator!template string}
 is a literal operator template whose \grammarterm{template-parameter-list}
 comprises
 a single \grammarterm{parameter-declaration} that declares a
-non-type template parameter of class type.
+constant template parameter of class type.
 The declaration of a literal operator template
 shall have an empty \grammarterm{parameter-declaration-clause}
 and shall declare either a numeric literal operator template