Generalize handling of leading spaces

[GB609]

Almost all line tests start with something like /^[[:space:]]*#/. This is completely redundant and complicates several of the advanced patterns much more than they have to be.
It's also boilerplate that makes adding new annotations more tedious.

The first modification of a line should be to detect surplus leading spaces and just strip them, e.g.

inserted at line 669, after the debug statement:

# strip any leading spaces
sub(/^[[:space:]]+#/, "#")

Once this is done, any test (and sub/gsub command) for annotations starting with /^[[:space::]]*# @.../ can be reduced to just /^# @.../.

[jbrubake]

Somewhat related, should all instances of [:blank:] be replaced by [:space:]? The former includes vertical spaces which is probably not helpful

[GB609]

I'm not sure about that. As far as i know, awk is line-based by nature. Thus you won't encounter linebreaks in normal line-by-line processing. So it's all about spaces and tabs.

[jbrubake]

You can do multi-line stuff with awk but it takes some additional manipulation that shdoc isn't doing. I'll see if I can use [:space:] everywhere

[GB609]

Does [:space:] include tabs? I wouldn't want to lose the ability to match them, as not everyone uses spaces for indication.

[jbrubake]

Good thing I double-checked the manual. I had them backwards (🤦‍♂️)

[:blank:] Space and TAB characters
[:space:] Space characters (these are: space, TAB, newline, carriage return, formfeed and vertical tab)
(https://www.gnu.org/software/gawk/manual/html_node/Bracket-Expressions.html)