Add LSP C/C++ editor content assist documentation

Also improve cross-referencing and mention decorated source file icons.

bundles/org.eclipse.cdt.lsp.doc/src/asciidoc/lsp_clangd_prefs.adoc

@@ -1,5 +1,5 @@
 ////
-Copyright (c) 2024 John Dallaway and others
+Copyright (c) 2024, 2025 John Dallaway and others
 This program and the accompanying materials
 are made available under the terms of the Eclipse Public License 2.0
 which accompanies this distribution, and is available at
@@ -41,4 +41,4 @@ image:lsp_clangd_prefs.png[width=550]
 
 Related concepts:
 
-* link:lsp_cpp_editor.html[C/C++ editor (LSP)]
+* xref:lsp_cpp_editor.adoc[C/C++ editor (LSP)]

bundles/org.eclipse.cdt.lsp.doc/src/asciidoc/lsp_content_assist_prefs.adoc

@@ -0,0 +1,38 @@
+////
+Copyright (c) 2025 John Dallaway and others
+This program and the accompanying materials
+are made available under the terms of the Eclipse Public License 2.0
+which accompanies this distribution, and is available at
+https://www.eclipse.org/legal/epl-2.0/
+
+SPDX-License-Identifier: EPL-2.0
+
+Contributors:
+    John Dallaway - initial content (#963)
+////
+
+// support image rendering and table of contents within GitHub
+ifdef::env-github[]
+:imagesdir: ../../images
+:toc:
+:toc-placement!:
+endif::[]
+
+= Content assist
+
+Use the image:command_link.png[] link:javascript:executeCommand('org.eclipse.ui.window.preferences(preferencePageId=org.eclipse.cdt.lsp.clangd.editor.contentAssistPreferencePage)')[Content Assist] preference page to configure the content assistance provided by the C/{cpp} editor (LSP):
+
+image:lsp_content_assist_prefs.png[width=550]
+
+.Content Assist Preference Options
+:!table-caption:
+[%autowidth]
+[options="header"]
+|===
+|Option              |Description
+|Fill function arguments and show guessed arguments |While editing a file, the editor will provide function argument assistance.
+|===
+
+Related concepts:
+
+* xref:lsp_cpp_editor.adoc[C/C++ editor (LSP)]

bundles/org.eclipse.cdt.lsp.doc/src/asciidoc/lsp_cpp_editor.adoc

@@ -1,5 +1,5 @@
 ////
-Copyright (c) 2024 John Dallaway and others
+Copyright (c) 2024, 2025 John Dallaway and others
 This program and the accompanying materials
 are made available under the terms of the Eclipse Public License 2.0
 which accompanies this distribution, and is available at
@@ -30,6 +30,8 @@ Projects created using an older version of CDT may be configured to use this edi
 
 image:lsp_editor_properties.png[width=526]
 
+When the C/{cpp} editor (LSP) is enabled for a project, source code files are presented with a decorated icon (image:lsp_decoration.png[]) in the _Project Explorer_ view.
+
 The C/{cpp} editor (LSP) includes the following features:
 
 - Syntax highlighting

bundles/org.eclipse.cdt.lsp.doc/src/asciidoc/lsp_cpp_editor_prefs.adoc

@@ -1,5 +1,5 @@
 ////
-Copyright (c) 2024 John Dallaway and others
+Copyright (c) 2024, 2025 John Dallaway and others
 This program and the accompanying materials
 are made available under the terms of the Eclipse Public License 2.0
 which accompanies this distribution, and is available at
@@ -35,4 +35,4 @@ image:lsp_editor_prefs.png[width=550]
 
 Related concepts:
 
-* link:lsp_cpp_editor.html[C/C++ editor (LSP)]
+* xref:lsp_cpp_editor.adoc[C/C++ editor (LSP)]

bundles/org.eclipse.cdt.lsp.doc/src/asciidoc/lsp_save_prefs.adoc

@@ -1,5 +1,5 @@
 ////
-Copyright (c) 2024 John Dallaway and others
+Copyright (c) 2024, 2025 John Dallaway and others
 This program and the accompanying materials
 are made available under the terms of the Eclipse Public License 2.0
 which accompanies this distribution, and is available at
@@ -35,4 +35,4 @@ image:lsp_save_prefs.png[width=550]
 
 Related concepts:
 
-* link:lsp_cpp_editor.html[C/C++ editor (LSP)]
+* xref:lsp_cpp_editor.adoc[C/C++ editor (LSP)]

bundles/org.eclipse.cdt.lsp.doc/toc_prefs.xml

@@ -15,6 +15,7 @@ Contributors:
 <toc link_to="../org.eclipse.cdt.doc.user/topics_Reference.xml#cdt_Preferences_Anchor" label="Editor (LSP) preferences">
 	<topic label="Editor (LSP) preferences" href="html/lsp_cpp_editor_prefs.html">
 		<topic label="clangd" href="html/lsp_clangd_prefs.html" />
+		<topic label="Content Assist" href="html/lsp_content_assist_prefs.html" />
 		<topic label="Save Actions" href="html/lsp_save_prefs.html" />
 	</topic>
 </toc>