Add missing qldoc

java/ql/lib/semmle/code/java/PrintAst.qll

@@ -167,6 +167,13 @@ class PrintAstNode extends TPrintAstNode {
    */
   Location getLocation() { none() }
 
+  /**
+   * Holds if this node is at the specified location.
+   * The location spans column `startcolumn` of line `startline` to
+   * column `endcolumn` of line `endline` in file `filepath`.
+   * For more information, see
+   * [Locations](https://codeql.github.com/docs/writing-codeql-queries/providing-locations-in-codeql-queries/).
+   */
   predicate hasLocationInfo(
     string filepath, int startline, int startcolumn, int endline, int endcolumn
   ) {

java/ql/lib/semmle/code/java/regex/RegexFlowModels.qll

@@ -1,3 +1,5 @@
+/** Definitions of data flow steps for determining flow of regular expressions. */
+
 import java
 import semmle.code.java.dataflow.ExternalFlow
 

java/ql/lib/semmle/code/java/regex/regex.qll

@@ -1,3 +1,7 @@
+/**
+ * Definitions for parsing regular expressions.
+ */
+
 import java
 private import RegexFlowConfigs
 
@@ -142,7 +146,7 @@ abstract class RegexString extends StringLiteral {
   }
 
   bindingset[x]
-  int max_zero(int x) { result = max([x, 0]) }
+  private int max_zero(int x) { result = max([x, 0]) }
 
   /**
    * Gets the nesting depth of character classes after position `pos`,
@@ -375,11 +379,13 @@ abstract class RegexString extends StringLiteral {
     not exists(int x, int y | this.backreference(x, y) and x <= start and y >= end)
   }
 
+  /** Holds if a normal character or escape sequence is between `start` and `end`. */
   predicate normalCharacter(int start, int end) {
     this.character(start, end) and
     not this.specialCharacter(start, end, _)
   }
 
+  /** Holds if a special character `char` is between `start` and `end`. */
   predicate specialCharacter(int start, int end, string char) {
     this.character(start, end) and
     end = start + 1 and
@@ -510,6 +516,7 @@ abstract class RegexString extends StringLiteral {
     this.simpleGroupStart(start, end)
   }
 
+  /** Holds if the text in the range start,end is a group with contents in the range in_start,in_end */
   predicate groupContents(int start, int end, int in_start, int in_end) {
     this.groupStart(start, in_start) and
     end = in_end + 1 and