man_pages - list man pages for word under cursor

[dsirov]

Description

1. Add a cword boolean option to list man pages for word under cursor.
2. Change the default section from 1 to ALL

This now allows a programmer to list all relevant man pages for the API word under cursor in the source code.
For example, for open(...), the list will be:

• open (3pm)
• open (2)

This resolves #3278

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Running telescope:

• Telescope man_pages
• Telescope man_pages cword=true
• Telescope man_pages sections={"2"} cword=true
• Telescope man_pages sections={"ALL"}
• Telescope man_pages sections={"1"} cword=false
• Telescope man_pages sections={"1"} cword=invalidstring
• Telescope man_pages sections={"1"} cword=1

Configuration:

• Neovim version (nvim --version):

NVIM v0.10.0
Build type: Release
LuaJIT 2.1.1713484068

• Operating system and version:
  Fedora 39

Checklist:

• My code follows the style guidelines of this project (stylua)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (lua annotations)