Adds missed functions into php_completions.js

[WinterSilence]

Issue #, if available:
#4546

Description of changes:
Adds missed functions (only popular)

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[codecov]

Codecov Report

Merging #4726 (5e488a0) into master (8f49d65) will decrease coverage by 0.08%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4726      +/-   ##
==========================================
- Coverage   71.19%   71.10%   -0.09%     
==========================================
  Files         553      554       +1     
  Lines       55598    55693      +95     
  Branches    10392    10421      +29     
==========================================
+ Hits        39584    39602      +18     
- Misses      16014    16091      +77     

Flag	Coverage Δ
unittests	71.10% <ø> (-0.09%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
lib/ace/mode/php_completions.js	26.08% <ø> (ø)
lib/ace/worker/mirror.js	51.35% <0.00%> (-9.26%)	⬇️
lib/ace/lib/dom.js	83.59% <0.00%> (-1.27%)	⬇️
lib/ace/ext/code_lens.js	91.60% <0.00%> (-0.48%)	⬇️
lib/ace/keyboard/textinput.js	75.45% <0.00%> (-0.26%)	⬇️
lib/ace/autocomplete/popup.js	78.19% <0.00%> (ø)
lib/ace/lib/es6-shim.js	15.85% <0.00%> (ø)
lib/ace/editor.js	79.66% <0.00%> (+0.01%)	⬆️
lib/ace/mouse/mouse_handler.js	83.59% <0.00%> (+0.26%)	⬆️
lib/ace/commands/command_manager.js	82.35% <0.00%> (+0.53%)	⬆️
... and 1 more

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