minirst: support passing admonitions into findadmonitions() and parse()

This will allow consumers to declare a custom list of admonitions
to parse. Without this patch, custom admonitions would get removed
when prunecomments() is run. We could add an argument controlling
whether prunecomments() is run. However, it is better to convert
the "paragraph" block to an "admonition" block so consumers don't
have to parse for custom admonitions.

mercurial/minirst.py

@@ -425,12 +425,14 b' def prunecomments(blocks):'
     'warning',
 ])
 
-def findadmonitions(blocks):
+def findadmonitions(blocks, admonitions=None):
     """
     Makes the type of the block an admonition block if
     the first line is an admonition directive
     """
-    admonitionre = re.compile(r'\.\. (%s)::' % '|'.join(sorted(_admonitions)),
+    admonitions = admonitions or _admonitions
+
+    admonitionre = re.compile(r'\.\. (%s)::' % '|'.join(sorted(admonitions)),
                               flags=re.IGNORECASE)
 
     i = 0
@@ -642,7 +644,7 b' def formathtml(blocks):'
 
     return ''.join(out)
 
-def parse(text, indent=0, keep=None):
+def parse(text, indent=0, keep=None, admonitions=None):
     """Parse text into a list of blocks"""
     pruned = []
     blocks = findblocks(text)
@@ -657,7 +659,7 b' def parse(text, indent=0, keep=None):'
     blocks = splitparagraphs(blocks)
     blocks = updatefieldlists(blocks)
     blocks = updateoptionlists(blocks)
-    blocks = findadmonitions(blocks)
+    blocks = findadmonitions(blocks, admonitions=admonitions)
     blocks = addmargins(blocks)
     blocks = prunecomments(blocks)
     return blocks, pruned