Docs command improvements

[Numerlor]

Improves the docs command by:

• Resolving symbol name conflicts
• Auto deleting commands that didn't find anything
• Improving output for docs of modules

closes: #538
closes: #210
closes: #381

[Numerlor]

any reason signature_buffer is not a list comp?

bot/bot/cogs/doc.py

Lines 210 to 219 in f194df8

	signature_buffer = []
	if symbol_heading is None:
	return None
	# Traverse the tags of the signature header and ignore any
	# unwanted symbols from it. Add all of it to a temporary buffer.
	for tag in symbol_heading.strings:
	if tag not in UNWANTED_SIGNATURE_SYMBOLS:
	signature_buffer.append(tag.replace('\\', ''))

[Numerlor]

Needs some further testing and going to take a look if I can implement #381 here

[Numerlor]

@jchristgit any reason 7d2b784 uses textwrap.shorten?
Want to get up to 3 signatures for cases where they exist but that collapses all the newlines

[Numerlor]

Some issues that I'm aware of but don't know if they should be looked into further:

• Notes and warnings like in cmath don't get put into blocks in embeds
• Some modules like glob don't get almost any info in their description because they start with a block of text that can't be cut off with the current logic
• Symbols linked to pages ending with .html can't be fetched
• A few thousand symbols similar to the format reference/page/normal_symbol_name exist as duplicates of normal symbols and can't be fetched through their name

Also not sure if the handling and logging of exceptions when fetching inventories is correct

[scragly]

A number of symbols have reduced usefulness after the changes. For example, list and multiprocess.Process both show the following:

This appears to be a generic page not tied to a specific symbol.

I feel like this still needs some work in order to improve consistency expected behaviour, as these cases actually had decent information output in the current version.

Another thing is I'd like to see a command added that will call refresh_inventory. If we add a new entry to the site, this ensures we can reload it without doing an internal eval.

[scragly]

One more bracket styling to fix (same as the previous ones but you added this one while removing the others). And adding back in some lost info after a comment was taken out.

[scragly]

Looks good to me now, thanks for your work!

[SebastiaanZ]

Looks good.