doc.kak: anchor/section completion support

rc/core/doc.kak

@@ -122,7 +122,17 @@ define-command -params 1 -hidden doc-render %{
 
 define-command -params 1..2 \
     -shell-candidates %{
+        if [ "$kak_token_to_complete" -eq 0 ]; then
             find "${kak_runtime}/doc/" -type f -name "*.asciidoc" | sed 's,.*/,,; s/\.[^/]*$//'
+        elif [ "$kak_token_to_complete" -eq 1 ]; then
+            readonly page="${kak_runtime}/doc/${1}.asciidoc"
+            if [ -f "${page}" ]; then
+                awk '
+                    /^==+ +/ { sub(/^==+ +/, ""); print }
+                    /^\[\[[^\]]+\]\]/ { sub(/^\[\[/, ""); sub(/\]\].*/, ""); print }
+                ' < $page
+            fi
+        fi
     } \
     doc -docstring %{doc <topic> [<keyword>]: open a buffer containing documentation about a given topic
 An optional keyword argument can be passed to the function, which will be automatically selected in the documentation} %{