Use template-parameter and template parameter more consistently

Try to use template-parameter only when we refer to a
grammar construct, and to 'template parameter' everywhere else.

Adopt the same logic to template-argument/template argument.

This change might not be  exhaustive.

The aim is to editorially adopt some of the wording changes
made in P2841R5 to ease its review in core.

Author: cor3ntin

source/basic.tex

@@ -2097,8 +2097,8 @@
 parameter types and return type.
 Additionally, if the aforementioned overload set is named with
 a \grammarterm{template-id}, its associated entities also include
-its template \grammarterm{template-argument}{s} and
-those associated with its type \grammarterm{template-argument}s.
+its template template arguments and
+those associated with its type template arguments.
 
 \pnum
 The \term{associated namespaces} for a call are

source/declarations.tex

@@ -773,7 +773,7 @@
 \indextext{class name!\idxcode{typedef}}%
 A \grammarterm{simple-template-id} is only a \grammarterm{typedef-name}
 if its \grammarterm{template-name} names
-an alias template or a template \grammarterm{template-parameter}.
+an alias template or a template template parameter.
 \begin{note}
 A \grammarterm{simple-template-id} that names a class template specialization
 is a \grammarterm{class-name}\iref{class.name}.
@@ -1652,8 +1652,8 @@
 the specification of the structured binding declaration;
 
 \item otherwise, if $E$ is an unparenthesized \grammarterm{id-expression}
-naming a non-type \grammarterm{template-parameter}\iref{temp.param},
-\tcode{decltype($E$)} is the type of the \grammarterm{template-parameter}
+naming a non-type 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};
 
@@ -3994,7 +3994,7 @@
 An abbreviated function template is equivalent to
 a function template\iref{temp.fct}
 whose \grammarterm{template-parameter-list} includes
-one invented type \grammarterm{template-parameter}
+one invented \grammarterm{type-parameter}
 for each generic parameter type placeholder
 of the function declaration, in order of appearance.
 For a \grammarterm{placeholder-type-specifier} of the form \keyword{auto},
@@ -4004,7 +4004,7 @@
 \grammarterm{type-constraint} \keyword{auto},
 the invented parameter is a \grammarterm{type-parameter} with
 that \grammarterm{type-constraint}.
-The invented type \grammarterm{template-parameter} is
+The invented \grammarterm{type-parameter} is
 a template parameter pack
 if the corresponding \grammarterm{parameter-declaration}
 declares a function parameter pack.
@@ -4013,7 +4013,7 @@
 The adjusted function parameters of an abbreviated function template
 are derived from the \grammarterm{parameter-declaration-clause} by
 replacing each occurrence of a placeholder with
-the name of the corresponding invented \grammarterm{template-parameter}.
+the name of the corresponding invented \grammarterm{type-parameter}.
 \begin{example}
 \begin{codeblock}
 template<typename T>     concept C1 = /* ... */;
@@ -4041,7 +4041,7 @@
 
 \pnum
 An abbreviated function template can have a \grammarterm{template-head}.
-The invented \grammarterm{template-parameter}{s} are
+The invented \grammarterm{type-parameter}{s} are
 appended to the \grammarterm{template-parameter-list} after
 the explicitly declared \grammarterm{template-parameter}{s}.
 \begin{example}

source/overloading.tex

@@ -3113,8 +3113,7 @@
 \item
 an explicit type conversion\iref{expr.type.conv,expr.static.cast,expr.cast}, or
 \item
-a non-type
-\grammarterm{template-parameter}\iref{temp.arg.nontype}.
+a non-type template parameter\iref{temp.arg.nontype}.
 \end{itemize}
 The \grammarterm{id-expression} can be preceded by the \tcode{\&} operator.
 \begin{note}
@@ -4098,7 +4097,8 @@
 A \defnx{string literal operator template}{literal!operator!template string}
 is a literal operator template whose \grammarterm{template-parameter-list}
 comprises
-a single non-type \grammarterm{template-parameter} of class type.
+a single \grammarterm{parameter-declaration} that declares a
+non-type 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