feat(lsp): add textDocument/rangeFormatting support

Advertise DocumentRangeFormattingProvider in server capabilities and
implement rangeFormat: formats the complete document, then returns an
edit covering only the minimal changed-line region that overlaps the
client's selection. Also includes gofmt alignment fixes across lint
and format packages.

pkg/format/body.go

@@ -215,13 +215,13 @@ func formatBodyStatements(text string, st config.Style) string {
 	rawLines := strings.Split(normalised, "\n")
 
 	var (
-		result       strings.Builder
-		stmt         []bline
-		parenDepth   int
-		blockDepth   int // 0=col-0 (BEGIN/END/EXCEPTION), 1=body, 2=nested…
-		inException  bool
+		result        strings.Builder
+		stmt          []bline
+		parenDepth    int
+		blockDepth    int // 0=col-0 (BEGIN/END/EXCEPTION), 1=body, 2=nested…
+		inException   bool
 		pendingBlanks int
-		depthInc     bool // increment blockDepth after next flush
+		depthInc      bool // increment blockDepth after next flush
 	)
 
 	flush := func() {