CLN: Deprecation of assert_

#7131: Run s/self.assert_(/self.assertTrue( on remaining instances I can find. These were the multi-line expressions, and I tried to retain the formatting of the expressions
CLN: Deprecation of assert_

Fix formatting of one multi-line assertion, from assert_ --> assertTrue cleanup
Merge pull request #7172 from bwignall/issue7131_assert_

CLN: Deprecation of assert_
BUG: fix isnull for 0d object arrays
Merge pull request #7176 from shoyer/isnull-0d-object-array

BUG: fix isnull for 0d object arrays
CLN: Deprecation of assert_

#7131: Fix two instances of assertEquals that naive grepping did not find
Merge pull request #7182 from bwignall/issue7131_assertEquals

CLN: Deprecation of assert_
DOC: some doc build fixes
Merge pull request #7185 from jorisvandenbossche/doc-fixes3

DOC: some doc build fixes
Update indexing.rst

Adding a warning, and example, about using attribute access to create a new column.
BUG: lookup global constants correctly in query/eval
Merge pull request #7181 from cpcloud/eval-with-inf

BUG: correctly lookup global constants in query/eval
Merge pull request #7188 from AllenDowney/patch-1

Update indexing.rst
BUG: bug in recognizing out-of-bounds positional list indexer with iloc and a multi-axis tuple indexer (GH7189)
Merge pull request #7189 from jreback/panel_iloc

BUG: bug in recognizing out-of-bounds on iloc indexers on tuple indexers (GH )
DOC: fix api doc build warning
BUG: Bug in setitem with a single item, and a multi-index and integer indicies (GH7190)
Merge pull request #7191 from jreback/loc_bug

BUG: Bug in setitem with a single item, and a multi-index and integer indices (GH7190)
BUG: Bug in expressions evaluation with reversed ops, showing in series-dataframe ops (GH7198)
CLN/DOC: add axis parameter doc for filter method