CC Mode: Add second anchor point to class-open and class-close

This fixes the second (last) part of bug#66911.  The new second
anchor points allow the indentation of braces in template
classes to be anchored on the keyword 'class' rather than the
`template' at the beginning of the statement.

* lisp/progmodes/cc-engine.el (c-add-class-syntax): Add &rest
args parameter for additional anchor points.  Pass these to
c-add-syntax.
(c-guess-continued-construct): CASE B.1: Note return value from
c-looking-at-decl-block and pass this to c-add-syntax for a
class-open construct.
(c-guess-basic-syntax): CASE 4: Duplicate anchor position for
class-open.
(c-guess-basic-syntax): CASE 5A.2: Note return value of
c-looking-at-decl-block and pass it as extra argument to
c-add-syntax for a class-open construct.
(c-guess-basic-syntax): CASE 5G: Call c-looking-at-decl-block
to determine the second anchor point for a class-close, and
pass it to c-add-class-syntax.

* doc/misc/cc-mode.texi (Class Symbols): Document the anchor
points for class-open and class-close.

1 files changed, 7 insertions, 0 deletions

diff --git a/doc/misc/cc-mode.texi b/doc/misc/cc-mode.texi
index 4ab95798468..8bc19235516 100644
--- a/doc/misc/cc-mode.texi
+++ b/doc/misc/cc-mode.texi
@@ -4507,6 +4507,13 @@ languages are syntactically equivalent to classes.  Note however that
 the keyword @code{class} is meaningless in C and Objective-C.}.
 Similarly, line 18 is assigned @code{class-close} syntax.
 
+Note that @code{class-open} and @code{class-close} syntactic elements
+have two anchor points.  The first is the position of the beginning of
+the statement, the second is the position of the keyword which defines
+the construct (e.g.  @code{class}).  These are usually the same
+position, but differ when the statement starts off with
+@code{template} (C++ Mode) or @code{generic} (Java Mode) or similar.
+
 @ssindex inher-intro
 @ssindex inher-cont
 Line 2 introduces the inheritance list for the class so it is assigned