replace dddoc with placeholder
[INTERNAL,DOC] remove more ddoc (hopefully last bits)

this removes ddoc that was incorrectly started with /* instead of /**

last commit:

```sh
for FILE in $(grep -l -R -E "^\.\.[^\.]+" apps include tests); do awk '$1 == "/*" { INCOMMENT = 1}; ($1 ~ /^\.\.[^\.]+/) && (OUTPUTOFF != 1) { print "_DDDOC_PLACEHOLDER"; OUTPUTOFF = 1; next }; $NF == "*/" { OUTPUTOFF = 0; INCOMMENT= 0
}; OUTPUTOFF != 1 { print }' $FILE > ${FILE}.new ; done

for FILE in $(find ./ -name "*.new"); do mv $FILE $(echo $FILE | sed -e 's/\.new//g'); done
```

this commit (plus some manual restoring of false positives and repeated calls) :
```sh
for FILE in $(ack -l DDDOC_PLACEHOLDER); do \
perl -0777 -i -pe 's|[\n]*\/\*[^\*]*\_DDDOC\_PLACEHOLDER[^\*]*\*\/[\n]*|\n\n|gs' $FILE; \
done
```
Merge pull request #745 from h-2/removeMoreDDDOC

Remove more dddoc