Improve documentation of 'read-regexp' and friends

* doc/emacs/glossary.texi (Glossary): Add "Tag" to the Glossary.
* doc/emacs/maintaining.texi (Xref): Mention that identifiers are
also known as "tags".

* lisp/replace.el (read-regexp, read-regexp-suggestions): Improve
wording of doc strings.  (Bug#46088)  (Bug#46089)

(cherry picked from commit 49eb03d6c8a181fd46adbbcf1f0a976d0a9efa87)

2 files changed, 18 insertions, 12 deletions

diff --git a/doc/emacs/glossary.texi b/doc/emacs/glossary.texi
index 35df06591eb..4f971eb1e01 100644
--- a/doc/emacs/glossary.texi
+++ b/doc/emacs/glossary.texi
@@ -1369,10 +1369,14 @@ configurations.  @xref{Tab Bars}.
 The tab line is a line of tabs at the top of an Emacs window.
 Clicking on one of these tabs switches window buffers.  @xref{Tab Line}.
 
+@item Tag
+A tag is an identifier in a program source.  @xref{Xref}.
+
 @anchor{Glossary---Tags Table}
 @item Tags Table
-A tags table is a file that serves as an index to the function
-definitions in one or more other files.  @xref{Tags Tables}.
+A tags table is a file that serves as an index to identifiers: definitions
+of functions, macros, data structures, etc., in one or more other files.
+@xref{Tags Tables}.
 
 @item Termscript File
 A termscript file contains a record of all characters sent by Emacs to
diff --git a/doc/emacs/maintaining.texi b/doc/emacs/maintaining.texi
index 14911d30e99..9bb3378c3f3 100644
--- a/doc/emacs/maintaining.texi
+++ b/doc/emacs/maintaining.texi
@@ -1860,19 +1860,21 @@ Of course, you should substitute the proper years and copyright holder.
 @section Find Identifier References
 @cindex xref
 
+@cindex tag
   An @dfn{identifier} is a name of a syntactical subunit of the
 program: a function, a subroutine, a method, a class, a data type, a
 macro, etc.  In a programming language, each identifier is a symbol in
-the language's syntax.  Program development and maintenance requires
-capabilities to quickly find where each identifier was defined and
-referenced, to rename identifiers across the entire project, etc.
-
-These capabilities are also useful for finding references in major
-modes other than those defined to support programming languages.  For
-example, chapters, sections, appendices, etc.@: of a text or a @TeX{}
-document can be treated as subunits as well, and their names can be
-used as identifiers.  In this chapter, we use the term ``identifiers''
-to collectively refer to the names of any kind of subunits, in program
+the language's syntax.  Identifiers are also known as @dfn{tags}.
+
+Program development and maintenance requires capabilities to quickly
+find where each identifier was defined and referenced, to rename
+identifiers across the entire project, etc.  These capabilities are
+also useful for finding references in major modes other than those
+defined to support programming languages.  For example, chapters,
+sections, appendices, etc.@: of a text or a @TeX{} document can be
+treated as subunits as well, and their names can be used as
+identifiers.  In this chapter, we use the term ``identifiers'' to
+collectively refer to the names of any kind of subunits, in program
 source and in other kinds of text alike.
 
 Emacs provides a unified interface to these capabilities, called