[std] Use template-parameter and template parameter more consistently (#7460)

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

@@ -2135,8 +2135,8 @@
 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

@@ -778,7 +778,7 @@
 \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}.
@@ -1671,8 +1671,8 @@
 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};
 
@@ -4068,7 +4068,7 @@
 
 \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

@@ -3103,8 +3103,7 @@
 \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}
 If the target type contains a placeholder type,
 placeholder type deduction is performed\iref{dcl.type.auto.deduct}, and
@@ -4100,7 +4099,8 @@
 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