feat(bash): add indents query

It's pretty basic at the moment but already makes working with bash
scripts way easier.

tests/indent/bash/test.sh

@@ -0,0 +1,39 @@
+for i in 1 2 3; do
+    if [[ true ]]; then
+        echo "asd"
+    elif [ true ]; then
+        echo "dsa"
+    else
+        echo ""
+    fi
+    echo $i
+done
+
+while true; do
+    break
+done
+
+case $foo in
+    a) echo a ;;
+    b) echo b ;;
+esac
+
+function x() {
+    echo x
+}
+
+y() {
+    echo y
+}
+
+{
+    echo z
+}
+
+(
+    echo subshell
+)
+
+A=$(
+    echo command substitution
+)

tests/indent/bash_spec.lua

@@ -0,0 +1,33 @@
+local Runner = require('tests.indent.common').Runner
+local XFAIL = require('tests.indent.common').XFAIL
+
+local run = Runner:new(it, 'tests/indent/bash', {
+  tabstop = 4,
+  shiftwidth = 4,
+  softtabstop = 0,
+  expandtab = true,
+})
+
+describe('indent Bash:', function()
+  describe('whole file:', function()
+    run:whole_file('.', {
+      expected_failures = {},
+    })
+  end)
+
+  describe('new line:', function()
+    run:new_line('test.sh', { on_line = 1, text = 'echo test', indent = 4 }) -- in "for"
+    run:new_line('test.sh', { on_line = 2, text = 'echo test', indent = 8 }) -- in "if"
+    run:new_line('test.sh', { on_line = 4, text = 'echo test', indent = 8 }) -- in "elif"
+    run:new_line('test.sh', { on_line = 6, text = 'echo test', indent = 8 }) -- in "else"
+    run:new_line('test.sh', { on_line = 8, text = 'echo test', indent = 4 }) -- after "fi"
+    run:new_line('test.sh', { on_line = 12, text = 'echo test', indent = 4 }) -- in "while"
+    run:new_line('test.sh', { on_line = 18, text = 'c) echo test ;;', indent = 4 }) -- in "case"
+    run:new_line('test.sh', { on_line = 21, text = 'echo test', indent = 4 }) -- in "function"
+    run:new_line('test.sh', { on_line = 25, text = 'echo test', indent = 4 }) -- in "f() { ... }"
+    run:new_line('test.sh', { on_line = 29, text = 'echo test', indent = 4 }) -- in "{ ... }"
+    run:new_line('test.sh', { on_line = 33, text = 'echo test', indent = 4 }) -- in subshell
+    run:new_line('test.sh', { on_line = 37, text = 'echo test', indent = 4 }) -- in command substitution
+    run:new_line('test.sh', { on_line = 39, text = 'echo test', indent = 0 })
+  end)
+end)