[doc] removed 'Reg_' from register anchors

Signed-off-by: Hugo McNally <hugo.mcnally@gmail.com>
diff --git a/util/mdbook_reggen.py b/util/mdbook_reggen.py
index cbee3a2..9f836c3 100755
--- a/util/mdbook_reggen.py
+++ b/util/mdbook_reggen.py
@@ -93,7 +93,7 @@
 
             name = reg[1] + "." + reg[2] if len(reg) == 3 else reg[1]
 
-            return "[`{}`]({}#Reg_{})".format(name, path, reg[1].lower())
+            return "[`{}`]({}#{})".format(name, path, reg[1].lower())
 
         chapter["content"] = REGREF_PATTERN.sub(regref_swap, chapter["content"])
 
diff --git a/util/reggen/gen_html.py b/util/reggen/gen_html.py
index d2b8eb5..04c172c 100644
--- a/util/reggen/gen_html.py
+++ b/util/reggen/gen_html.py
@@ -185,14 +185,14 @@
     # we also insert a label without the index so
     # that unnumbered links from the register table
     # descriptions and Hugo-generated docs are possible.
-    if rname[-2:] == "_0":
-        mr_anchor = ('id="Reg_{}"'
+    if rname[-2:] == "0":
+        mr_anchor = ('id="{}"'
                      .format(rname[:-2].lower()))
     else:
         mr_anchor = ''
 
     genout(outfile,
-           '<table class="regdef" id="Reg_{lrname}">\n'
+           '<table class="regdef" id="{lrname}">\n'
            ' <tr>\n'
            '  <th class="regdef" colspan=5 {mr_anchor}>\n'
            '   <div>{comp}.{link} @ {off:#x}</div>\n'
@@ -324,7 +324,7 @@
     wname = win.name or '(unnamed window)'
     offset = win.offset
     genout(outfile,
-           '<table class="regdef" id="Reg_{lwname}">\n'
+           '<table class="regdef" id="{lwname}">\n'
            '  <tr>\n'
            '    <th class="regdef">\n'
            '      <div>{comp}.{link} @ + {off:#x}</div>\n'
diff --git a/util/reggen/html_helpers.py b/util/reggen/html_helpers.py
index 02ba6da..b55ea4c 100644
--- a/util/reggen/html_helpers.py
+++ b/util/reggen/html_helpers.py
@@ -9,7 +9,7 @@
 
 def get_reg_link(rname: str) -> str:
     '''Return regname with a HTML link to itself'''
-    return '<a href="#Reg_{}">{}</a>'.format(rname.lower(), rname)
+    return '<a href="#{}">{}</a>'.format(rname.lower(), rname)
 
 
 def expand_paras(s: str, rnames: Set[str]) -> List[str]:
@@ -55,10 +55,10 @@
         mr_names = set([base + "_0", base + "_1"])
         if base in rnames or len(rnames & mr_names) == 2:
             if match.group(1)[-1] == ".":
-                return ('<a href="#Reg_' + base + '"><code class=\"reg\">' +
+                return ('<a href="#' + base + '"><code class=\"reg\">' +
                         match.group(1)[:-1] + '</code></a>.')
             else:
-                return ('<a href="#Reg_' + base + '"><code class=\"reg\">' +
+                return ('<a href="#' + base + '"><code class=\"reg\">' +
                         match.group(1) + '</code></a>')
         log.warn('!!' + match.group(1).partition('.')[0] +
                  ' not found in register list.')