toplevel: unify the GCC and GDB/binutils .editorconfig files

Both GCC and GDB/binutils now have root editorconfig files.  It would
make sense to unify them as this sets the general tone for these
projects.

ChangeLog:
	* .editorconfig: Unify the GCC and GDB/binutils root config.

.editorconfig

@@ -1,4 +1,4 @@
-# Copyright 2022 Free Software Foundation, Inc.
+# Copyright 2025 Free Software Foundation, Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -19,6 +19,10 @@
 #
 #   https://editorconfig.org/
 
+# This file is common to the GCC and GDB/Binutils projects.  If you
+# update one, please sync it with the other.
+
+# top-most EditorConfig file
 root = true
 
 [*]
@@ -26,22 +30,113 @@ end_of_line = lf
 insert_final_newline = true
 tab_width = 8
 
+# EditorConfig files
+[.editorconfig]
+charset = utf-8
+trim_trailing_whitespace = true
+
 # Makefile
-[{Makefile*,*.mk}]
+[{Makefile,*.mk,*.am}*]
 indent_style = tab
 indent_size = 8
+trim_trailing_whitespace = true
+
+# ChangeLogs
+[ChangeLog*]
+indent_style = tab
+indent_size = 8
+trim_trailing_whitespace = true
+charset = utf-8
 
 # C/C++
 [*.{c,h,cc}]
+charset = utf-8
 indent_style = tab
 indent_size = 2
+trim_trailing_whitespace = true
+
+# GCC .def files.  These are generally C fragments that get included
+# one or more times
+[gcc/**.def]
+charset = utf-8
+indent_style = tab
+indent_size = 2
+trim_trailing_whitespace = true
+
+# Texinfo files
+[*.texi]
+charset = utf-8
+indent_size = 2
+trim_trailing_whitespace = true
 
 # Expect / TCL
 [*.{exp,tcl}]
 indent_style = tab
 indent_size = 4
+trim_trailing_whitespace = true
 
 # Python
 [*.py]
 indent_style = space
 indent_size = 4
+trim_trailing_whitespace = true
+
+# Assembler
+[*.{s,S,asm}]
+indent_style = tab
+indent_size = 8
+trim_trailing_whitespace = true
+
+# GCC Machine description files
+[gcc/config/**.md]
+indent_style = tab
+indent_size = 2
+trim_trailing_whitespace = true
+
+# Awk
+[*.awk]
+indent_style = tab
+indent_size = 2
+trim_trailing_whitespace = true
+
+# Autoconf
+[*.{ac,m4}]
+indent_style = tab
+indent_size = 2
+trim_trailing_whitespace = true
+
+# Shell scripts
+[*.sh]
+indent_style = tab
+indent_size = 4
+trim_trailing_whitespace = true
+
+# Ada
+[*.ad[bs]]
+indent_style = space
+indent_size = 3
+trim_trailing_whitespace = true
+
+# D
+[*.d]
+indent_style = space
+indent_size = 4
+trim_trailing_whitespace = true
+
+# Go
+[*.go]
+indent_style = tab
+indent_size = 8
+trim_trailing_whitespace = true
+
+# Fortran
+[*.[Ff]90]
+indent_style = space
+indent_size = 2
+trim_trailing_whitespace = true
+
+# Cobol
+[*.cbl]
+indent_style = space
+indent_size = 2
+trim_trailing_whitespace = true