New "dummy-section-header" trigger in inflmap

The new Swahili not-so-mega tables have a problem in that there are too
many <table> elements that break the flow of our parser, a bit needlessly.
When "Infinitives" in a separate <table>...Infinitives</table> from the
data it should be heading (<table>...positive: blah...</table> it can't
propagate, even with the old header-saving subsystem devised for the
original Swahili megatable (see those commits).

To fix this, using TableContext we introduce a new context-variable called
TableContext.section_header which should contain the tag data of the
current "section" being parsed, within a table with subtables.

When inflmap finds the dummy-tag "dummy-section-header" it will save the
tag data (of only one, the first) where it encounters it in a sect of tag
alternatives into TableContext.section_header, and then later joins that
data in the data of the cells.

When it encounters dummy-section-header the next time, it will replace the
tag data with the new section data.

Author: kristian-clausal

wiktextract/inflection.py

@@ -1699,6 +1699,7 @@ def merge_row_and_column_tags(form, some_has_covered_text):
                 tags.update(extra_tags)
                 tags.update(rt)
                 tags.update(refs_tags)
+                tags.update(tblctx.section_header)
                 # Merge tags from column.  For certain kinds of tags,
                 # those coming from row take precedence.
                 old_tags = set(tags)
@@ -1810,6 +1811,7 @@ def merge_row_and_column_tags(form, some_has_covered_text):
                                    "dummy-store-hdrspan",
                                    "dummy-load-stored-hdrspans",
                                    "dummy-reset-stored-hdrspans",
+                                   "dummy-section-header",
                                    ])
 
                 # Perform language-specific tag replacements according
@@ -2034,6 +2036,10 @@ def merge_row_and_column_tags(form, some_has_covered_text):
                             new_hdrspans.append(hdrspan)
                     hdrspans = new_hdrspans
 
+                for tt in v:
+                    if "dummy-section-header" in tt:
+                        tblctx.section_header = tt
+                        break
                 # Text between headers on a row causes earlier headers to
                 # be reset
                 if have_text:
@@ -2581,10 +2587,12 @@ class TableContext(object):
     """Saved context used when parsing a table and its subtables."""
     __slot__ = (
         "stored_hdrspans",
+        "section_header",
         "template_name",
         )
     def __init__(self, template_name=None):
         self.stored_hdrspans = []
+        self.section_header = []
         if not template_name:
             self.template_name = ""
         else: