[Feature] `gq`/`gw` format operators

[WilliamCappelletti]

gw and gq are very useful for formatting text (in particular, for word-wrapping large paragraphs).

Operator documentation:

gq{motion}		Format the lines that {motion} moves over.
			The cursor is left on the first non-blank of the last
			formatted line.
gw{motion}		Format the lines that {motion} moves over.  Similar to
			|gq| but puts the cursor back at the same position in
			the text.

They were requested for codemirror5 in codemirror/codemirror5#5529