simplify sed for docgen

hack/update-enum-docs.sh

@@ -7,9 +7,9 @@ md_file="./docs/api.md"
 grep "placeholder @" "$md_file" | while read line; do
     type=$(echo "$line" | sed -r 's/^placeholder @(.*):(.*)@/\1/')
     indent=$(echo "$line" | sed -r 's/^placeholder @(.*):(.*)@/\2/')
-    repl=$(go doc -all -short -C pkg/api $type | sed -r ':x ; /\/\// { N ; s/\/\/ (.*)\n/\1##/ ; bx }' | grep "##" | sed -r "s/\s*(.*)##.*\"(.*)\"/$(printf "%${indent}s")\2: \1/")
+    repl=$(go doc -all -short -C pkg/api $type | grep "MetricFilterEnum =" | sed -r "s/^.*\"(.*)\".*\/\/ (.*)/$(printf "%${indent}s")\1: \2/")
     awk -v inject="${repl}" "/placeholder @$type:$indent@/{print inject;next}1" $md_file > "$md_file.tmp"
+    rm $md_file
+    mv "$md_file.tmp" $md_file
 done
 
-rm $md_file
-mv "$md_file.tmp" $md_file

pkg/api/encode_prom.go

@@ -60,18 +60,13 @@ type MetricsItem struct {
 type MetricFilterEnum string
 
 const (
-	// match exactly the provided filter value
-	MetricFilterEqual MetricFilterEnum = "equal"
-	// the value must be different from the provided filter
-	MetricFilterNotEqual MetricFilterEnum = "not_equal"
-	// filter key must be present (filter value is ignored)
-	MetricFilterPresence MetricFilterEnum = "presence"
-	// filter key must be absent (filter value is ignored)
-	MetricFilterAbsence MetricFilterEnum = "absence"
-	// match filter value as a regular expression
-	MetricFilterRegex MetricFilterEnum = "match_regex"
-	// the filter value must not match the provided regular expression
-	MetricFilterNotRegex MetricFilterEnum = "not_match_regex"
+	// For doc generation, enum definitions must match format `Constant Type = "value" // doc`
+	MetricFilterEqual    MetricFilterEnum = "equal"           // match exactly the provided filter value
+	MetricFilterNotEqual MetricFilterEnum = "not_equal"       // the value must be different from the provided filter
+	MetricFilterPresence MetricFilterEnum = "presence"        // filter key must be present (filter value is ignored)
+	MetricFilterAbsence  MetricFilterEnum = "absence"         // filter key must be absent (filter value is ignored)
+	MetricFilterRegex    MetricFilterEnum = "match_regex"     // match filter value as a regular expression
+	MetricFilterNotRegex MetricFilterEnum = "not_match_regex" // the filter value must not match the provided regular expression
 )
 
 type MetricsItems []MetricsItem