Bug: zynthian.org - Fix spelling and improve wording of Engines #1427

Describe the bug
Fix spelling and improve wording of Engines summary and detail pages

https://zynthian.org/engines#synthesizer

1. ZynAddSubFX: the more amazing sounds -> the most amazing sounds
2. Dexed: from 1980s -> from the 1980s
3. Monique: excelent -> excellent
4. inspired on -> inspired by (multiple places)

https://zynthian.org/engines/_engine-list/engine-zynaddsubfx

1. a category all its own -> a category of its own
2. will enjoy from -> will enjoy it from
3. this makes possible to use more than one instrument for a single part. It is possible to choose what items from the kit should be processed by the Part's effects. -> choose uppercase or lowercase for part in both sentences
4. The link to the Project's Website, gives a DNS_PROBE_FINISHED_NXDOMAIN in my web brower. The github page mentions the working http://zynaddsubfx.sf.net

https://zynthian.org/engines/_engine-list/engine-setbfree

1. MIDI-controlled, software synthesizer -> MIDI-controlled software synthesizer
2. All controls can be dynamically bound to MIDI-CC messages as needed (there are default config files for common keyboards such as the Kurzweil 2500 or Oxygen61 included). -> All controls can be dynamically bound to MIDI-CC messages as needed. Default config files for common keyboards such as the Kurzweil 2500 or Oxygen61 are included.
3. Interaction with the synth is done can be done -> Interaction with the synth can be done
4. incoming MIDI message -> incoming MIDI messages
5. midi-keyboard -> MIDI-keyboard

https://zynthian.org/engines/_engine-list/engine-linuxsampler

1. It's capable of streaming audio samples directly from disk, what allows to manage soundfont files much bigger than the available physical memory. -> It's capable of directly streaming audio samples from disk, supporting soundfont files much bigger than the available physical memory.

https://zynthian.org/engines/_engine-list/engine-dexed

1. original math limitation -> original math limitations
2. Each operator have -> Each operator has
3. sysex/Sysex -> choose lowercase or uppercase and apply it in this page

https://zynthian.org/engines/_engine-list/engine-obxd

1. rather than smooth -> rather than smoothly
2. increases CPU consumption slightly -> slightly increases CPU consumption
3. allows to transition -> allows transitioning
4. but also interacts with the LFO rate knob in interesting ways as well. -> 4. but also interacts with the LFO rate knob in interesting ways. (as well is redundant with the also)

https://zynthian.org/engines/_engine-list/engine-epiano

1. It emulates quite nicely -> It quite nicely emulates
2. It has a few options only -> It only has a few options
3. muffle and hardness -> Muffle and hardness
4. MDA's website http://mda.smartelectronix.com is giving me a timeout, unclear if the site is still alive.

https://zynthian.org/engines/_engine-list/engine-noizemaker

1. tecno-dance music -> techno-dance music 🕺
2. The link to LV2 Source Code gives a 404

https://zynthian.org/engines/_engine-list/engine-helm

1. The 'h' button provides adds -> The 'h' button adds
2. Along with the oscillators are a sub-oscillator -> Along with the oscillators there is a sub-oscillator (don't know Helm enough to know if this is limited to one)